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INT€RCOMPUT€R IMC.

Expands the use of your TIMEX SINCLAIR COMPUTERS

SOFTBOXT

• Expands the expansion port of your Timex Sinclair
computer

• Has 4 gold plated, fully buffered ports

• Software selectable, any desired port /ports

• Longer life to your computer console and program
cartridge

• Has LED indicator, on/off switch and DC power input jack

• Provides power to your computer and peripherals

• E li m mat es t h e co m pu t er o ve r I o ad i n g and peri pheraf

connection problems #PL7012 $59. 9S

Neittis flexible nbbon connector; mti be available for TSlSGG anti TSSOOO computes

DATA COMMUNICATION PACKAGE

• Now your Timex computer can communicate directly on your
telephone line with other computers and data base networks such
as COMPUSERVE. DOW JONES NEWS RETRIEVAL, etc
1. "J-CAT” Modem by NOVATION. 0-300

BAUD #PL7017

2. RS232 Interface

#PL700e

a Connecting Cable

#PL7018

PACKAGE including items 1, 2, & 3

#PL7020

PRINTER’S PACKAGE

Our printer package enables you to printout
all the received information

1. SEIKOSHA GP100, 9 Inch Printer

2. MEMOTECH Centronics Interface

$129.95

$9995

$1995

$197.95

3. Printer Cable

QSAVE

A Reliable Fas! Loading System

• Operates 16 times faster than the
Sinclair system (i.e. Loads /Saves 8K in
10 secs; 48K in 110 secs)

• Operates with any memory and on any
program length

• Works equally welt with AUTORUN
programs, BASIC or MACHINE CODE

• This is what you get:

1. A cassette interface to improve the
signal quality, To make loading most
reliable an AUTOMATIC LEVEL
CONTROL, an OVERLOAD
WARNING LIGHT, a SAVE/LOAD
SWITCH, an ON/OFF SWITCH are
also built into this unit.

2. Highly sophisticated, superbly easy to

use 1/2K software for up to 16K and
64K programs #p|_7001 $37.95

MCODER (16K RAM)

FLEXIBLE RIBBON

• The first real integer BASIC compiler

CONNECTOR

#PL7019 $29995

MEMOTECH PRODUCTS

MEMOPAK 16K #PL7002 $44.95

MEMOPAK 32K #PL7O03 $89.95

MEMOPAK 64K #PL7004 $134.95

HIGH RESOLUTION GRAPHICS

#PL7007 $89,95

KEYBOARD #PL7011 $89.95

MEMOCALC #B$2001C $53.95

MEMOTEXT #PL7014 $44.95

MEMOASSEMBLER #PL7015 $44.95

for the TS1000 computer
Give your BASIC program the speed
of MACHINE language programs
75 times and in some cases up to 900
times speed improvement
Very simple to use:

1 Load MCODER
2. Write your BASIC program
according to the manual and
compile it through the MCODER by
using a single PRINT USR
command

BASIC programs can be compiled and
"Stacked1' above each other in memory

#PL4001 $18.95

ASSEMBLER/DEBUGGER
“ZXAD” {16K RAM)

Write machine code quickly and easily
Two pass assembler. ZILOG mnemonics,
8 pseudo- OPS
Debugger includes
examine/modifying, breakpoint with
register display

Occupies 7K, comprehensive multi¬
page manual

#PT4Q03 $18.95

STOPPER

Enables you to break through any
machine code software, list it on the
screen, save it on another tape, or
print it out

Very simple to use, load STOPPER
into your TS1000 and follow the simple
instructions on the screen

#PT4002 $18.95

All products are compatible with TSIOOOand TS1 500 Computers

For more information, cirde 33 on reader service card.

No More System Crashes

• Conn ects any R A M ex pans i 0 n to you r
TS1000

• Prevents usual system crashes caused
by the computer or the RAM movement

• 7 inches long flat ribbon cable

#PL7016 $17.95

DEALERS/DISTRIBUTORS PACKAGE
AVAILABLE.

Phone orders: (€17) 738-5310 7 days a week.

Gall or write to us for FREE brochure and
information on our full line Ot software.

Mail lo: Intercomputer, inc., PO. Box 90

Prudential Center, Boston. MA 02199
Tel: (617) 738-5310
Telex 951141COFAR

DISASSEMBLER

(Decoding Tool)

On Solid State Cartridge

• Disassemble any assembly language
code on memory

• Assembly language games and other
, programs

#PT4004 $34.95

Heeds Flexible Ribbon Connector or Soft box

PART#

QTY.

UNIT

u.s. $

TOTAL

Shipping and Handling
(or MEMOTECH and QSAVE

4.95

for EACH PACKAGE

9.95

Mass. Residents Tax 5%

Total

□ Visa □ M C □ Check

Account No.
Name

Exp

Adckess

City

State

. Zip '

No Shipping A Handling Charges for Cassettes

“GET ACQUAINTED” OFFER

GET TWO TimeUJCRtCS PROGRAMS

When You Buy

TimeuicR(<s

“Computer

Control

Center”™

For Timex-Sinclair 1 000 and
Sinclair ZX-81 Computers.

Only $9095

A handsome, compact work station that consolidates work
space and provides remarkably taster, easier operation!
Features:

• Effectively eliminates cluttered
cables in your work area.

• ON/OFF Switch eliminates
plugging and unplugging.

• Accommodates all brands of
16Kt 32K, 64 K RAM packs.

• Allows provision for one Print¬
er and Tape Deck hook-up.

• Holds your Software tapes in
neat, specially formed
pockets.

• High impact, black molded
plastic. 3W high, 20" deep,
14V2" wide.

• Accommodates a 13" TV
screen.

Any Two TIMEWORKS Programs Listed
Below with the " Computer Control
Center" (retail value $16.95 ea.)

Cat, No

1101 THE QUIZ KIT™ Educational
learning system. Construct
your own quizzes. 16K Req.

1201 5-2 GAMES™ Five challeng¬
ing and entertaining games.
2K Req

1202 STAR BATTLE™ Realistic
deep space adventure to
save Earth. 16K Req.

1203 ROBBERS OF THE LOST
TOMB™ Perilous adventure
in search of the Sacred Tab¬
lets. 16K Req

1 204 WALL STREET™ A competi¬
tive game of financial spec¬
ulation. 16K Req.

1205 PRESIDENTIAL CAMPAIGN™

Conduct a nationwide cam¬
paign to become the next
President of the United
States. 16k Req.

1 207 SCYON'S REVENGE™ Real¬
istic deep space combat ad¬
venture. 16K Req.

1301 THE MONEY MANAGER

Home and business budget
and cash flow system. 16K
Req.

Cat, No

1302

THE COLLECTOR'S COM¬
PANION™ Cataloging and
inventory recording system
for all collectibles. 16K Req.

1303 THE INSURANCE PROPER¬
TY RECORD™ Home con¬
tents inventory recording
system. 16K Req.

1304 THE ELECTRONIC CHECK*
BOOK™ Check recording,
sorting and balancing sys¬
tem. 16K Req.

1306 FORGET-ME-NOT™ A re¬
cording and retrieval system
for important occasions,
events and appointments.
16K Req,

1307 DATA MASTER™ A general
information storage and re¬
trieval system— with exclu¬
sive “X-SEARCH '™ Fea¬
ture. 16K Req.

1308 5-2K FAMILY PAK™ 5

Household programs for the
basic T/S 1000 and Sinclair
ZX-81 Computers, 2K Req.
[i* 1401 PROGRAMMING KIT 1“ A
practical M How-To" learning
approach to Basic program¬
ming, 16K Req.

mbr

DISTRIBUTORS

P.O. Box 321 . Deerfield. IL 6001 5 (312) 291-9284

for

$5400

$2995

value

$34°s

GUARANTEE

iny reason, you are not completely satisfied, you may
The Computer Control Center, in good condition

You save

COMPLETE MONEY BACK GUARANTEE

If, for any

return The Computer Control Center, in good
(freight prepaid), for a full cash refund. (Software not
included).

RUSH This Coupon Today.

M BR Distributors PO Box 321 Deerfield, I L 600 1 5

Rush me _ Computer Control Centers @ $29,95/ea

Plus postage A handling _ @ $4.70/ea

(Illinois residents add 6% sales tax}

ALSO INCLUDE TWO FREE PROGRAMS
(Additional Software @ $16.95 ea)

Cat. No, Qty.

@ no charge
@ no charge
@$l6.95/ea
@$16.95/ea
TOTAL

N/C

Name _

Address .

City _

. State .

.Zip.

Check or MO □
Card No. _____
Signature .-

VISA □ Master Charge □

American Express □
_ Exp, Date _ _

Dept.

For more information* circle 1 on reader service card.

AN EARLY STEP

One of -the first steps Q *

to wa rd a rea / computer ff ^ q{q |
was taken at Iowa State ^

University between 1921 and fg

J. A tanasotf and C. Berry planned
an "electronic binary digital
equation solver!' ihty never
completed the project bat
the concept r tout red an
internal storage system,
c>ne at the crireria. -for a.
computer. A very early step in
the many needed to get us ft the
computers of today !

A GIANT STEP

If necessity is the
mother of invention,
then World War 1 Z
certainly ranks as an
in rent ion generator.
Computers were needed
immediately for flight
Simulators t radar, code
breaking, gun control and
personnel training ,
it's an ill wind .

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Use your KOLORWORKS immediately
with a game cassette for $9.95

"A */4 1 LAB L E AT L OCA L
m RETAILERS09

Shipping and Handling 4.95
WL residents add safes tax

□ VISA □ Mastercard

Qcheck □ money order

MAIL TO:

BRAINCHILD COMPUTER WORKS, INC.

P.0. Box 506
Pewau kee, Wl 53072

Please allow six to eight weeks for processing.

For more information, cirde 42 on reader service cord.

President

Terry Cartwright

Editor-in-Chief

John Sterliechi

Managing Editor

Joseph Gladstone

Art Director

Vladyana Krykorka

Production Editor

Bill Gladstone

Associate Artists

Gwen Egan
Don Kletke

Katarina Altrichter-Raksany

Editorial Assistant

Becky Ashwell

Chairman
Richard Hease

For SUBSCRIPTIONS
Phone 800-543-3000
Operator 243

Timex Sinclair User is
published monthly by ECC
Publications Inc. in
conjunction with C.W*

Co m m u nic atio ns/I n c ,

If you would like to
contribute to Timex Sinclair
User, please send programs,
articles or ideas for hardware
projects to:

Timex Sinclair User
49 LaSalle Avenue
Buffalo, N.Y. 14214

Programs should be on
cassette and articles should
be typed and double spaced.

If you wish your material
returned, enclose a stamped ,
self-addressed envelope.

We pay $20 for each program
published and $100 per 1,000
words for each article used.

Typesetting by
International Typesetting
Printing by

Clark Franklin Kingston Press

Advertising Sales
Bill York
Hajar Associates
(617) 444-3946

Programming Arcade Games, page 58.

T/S Entrepreneurs, page 54.

SOFTWARE _ _

Ten new reviews and the “Previously Reviewed'' capsules

LETTERS _

In which our readers have their say

TIMEXPECTATIONS _

Can Timex maintain its Image of cloddike efficiency?

BOOKS _

Logan's and O'Hara's ROM disassembly guide is invaluable

COVER _ _

Jim Stephens shows how to convert your computer to color

HOW TO PROGRAM _ _

Jn the last part of his series, John Gilbert deals with finding hugs

PROGRAM PRINTOUT _ _

Compoetry, Video Graphity, Kingdom Revisited and other great programs

A high-resolution non-glare screen monitor; and more

NEWS

Timex is expediting delivery of the long-awaited 2000-series

FEATURE

_ 41

Kwikploi: a program for investigating correlations

IN-DEPTH

Merging in basic: How to do what the manual says you can't

ILK. WINDOW

Britain's software pioneer days are over

HINTS ft TIPS

On locking your computer, saving memory, rubber bands and more

USER GROUPS

Four companies have sprung from one Pennsylvania group

USER GROUPS

Is your group included in our updated listing?

FEATURE

How to Program Arcade Games: Part I of a series by Bob Fraser

BULLETIN BOARD

New products and information of interest to T/S users

• Joysticks for
your T/S

• Programming Arcade
Games Part II

and much more!

TIMEX SINCLAIR USER

Spaced Out

MOTHERSHIP

Saftsync, 16K

The object of Mothership
is to protect your Starlight
Fighter Ship from the at¬
tacking Mothership as you
race down the Zarway
space corridor. You ac¬
cumulate points by direct
hits on the Mothership's
missiles. There are three
levels of play, with a one or
two player option.

The graphic effects are
excellent in this fast-paced,
arcade-style game. You can
fly your Starlight Fighter
through the space corridor
(being careful not to crash
into the walls), or just lay
low and blow up the drone
fighters sent out by the
Mothership. The one or two
player option lets you pit
your maneuvering skill
against other fighter
pilots,

and the different levels of
play add to the versatility
and fun of this game.
My high score so far
is 16,300. See if you can
beat that! * + *

For more informo ti on, circle 2 on
reader service card.

Reviews

11 Varieties

GAMESTAPE 1

Melbourne House, 16K

This tape holds 11 games
for the unexpanded
T/SlOOO, Although their
quality is not uniform, the
variety is impressive, and
Klingons, Code, Asteroids
and Breakout are good
enough in themselves to
justify purchasing this tape.
In Klingons you try to ram
the ships approaching you;
Code is a guessing game
along the lines of Master¬
mind; Asteroids gives you
only one direction control
to avoid hunks of debris;
and Breakout is a ball and
paddle game with a twist
Others include Simon, a
word version of the popular
children's game; :

UFO, a shooting mr ^0
gallery type
of game;

Fore!

GRAPHIC GOLF

Mind wore, 16K

Graphic Golf takes you to
the first hole on an 18 hole
game of golf. As in real golf¬
ing, the object is to play
each hole under par. The
golfer encounters such
obstacles as sand traps,
trees and water, and must
also cope with wind, which
can affect the direction of a
shot. JmSm

This game allows you to
play golf in any weather
without special equipment.
When you tee off at each
hole the computer is your
caddy, asking you to choose
your golf club (choice of

Bomber, in which
you get ten runs to destroy a
dam; and Guillotine, which
is Hangman revisited. For
players accustomed to a
larger memory capacity, the
games may prove
frustrating in their simplici¬
ty. + **

For more in/ormatjon, circle 3 on
reader service card.

wood, iron, or putter], and
club size. You are then ask¬
ed to indicate the direction
the ball is to travel (up,
down, left, right), the angle
it is to take, and the driving
force behind your shot. If
you lose your ball in the
trees or water you must tee
off again. Each hole is clear-

ly displayed in graphics*
and ail 18 are different.
After playing each hole you
are given a running tally as
well as your score for the
hole just played. Graphic
Golf is an absorbing game
which relies on skill and
good judgment. The player
sets his own handicap so it
is possible to increase the
difficulty of the game as
your skills improve. * * *

For more inform cdiuft* circle 4 on
reader service card

Superlative

MAZOGS

Bug Byte, 16JC

Wow! This is one of the
best programs Fve
ever seen.
/ 1 couldn't

get to the
5 machine to

try it myself
because my kids (ages 10
and 11) were always there!
The graphics are really ef¬
fective.

You are at the edge of a
large and complicated
maze. The maze contains
several prisoners who will
always help you find the
treasure and the exit. There

TIMEX SINCLAIR USER

are also a number of
swords, which are useful to
fight the Mazogs you will
encounter

The game is played in the
three levels of difficulty
which correspond to dif¬
ficult through suicidal. You
have a view of just a tiny
portion of the maze but can
request a full screen view at
any time.

If you don't have Mazogs
you're missing the best
game for Sinclair com¬
puters — it might be the
best game for any com¬
puter. The whole family lov¬
ed it! ★* **

For more information, cirde 5 on
reader service card.

Batball

WALLBUSTERS

Beam Software , IK
This batting game
features speed and smooth
action. The player has a
choice of seven speeds, pro¬
viding a challenge to ex¬
perts as well as beginners.
The object is to clear all
three walls, involving a cer¬
tain amount of skill. A
limitation of the game is
that in order to change the
speed at which you are
playing, the game must be
reloaded. Also clearing all
three walls ends the game.
In play, however, this game
should please any batting-
game enthusiast . * ★ Vi

For more information, cirde 6 on
reader service card.

Treasure

Hunt

CAVES OF ZULU

Stuart Software, 16K

This combination word-
adventure and maze game
was created with humor
and imagination. The object
is to collect treasures hid¬
den in a maze; as the player
travels through, walls and:
hazards come into view.
Each treasure ip worth
points, although nothing is
done with your score othef
than adding it up. There are
three levels of difficulty:
level one is almost too easy,
level two is good and level
three is sometimes impossi¬
ble. Graphics are used well
to accent your moves.
However, the game is very
slow. There is also a tenden¬
cy to go into a loop on one
or two specific moves. This
is, unfortunately, a good
idea not reaching its full
potential.

For more information . cirde 7 on
reader service card.

For Budding
Jedis

VAULT OF THE
CENTAURS

Orbyte Software, 16K

In Vault Of The Centaurs
you must capture the life
fuel Zykon

War Game

COMBAT FLIGHT

Melbourne House, 16K
Put yourself at the con¬
trols of a fighter ship flying
over a mountain range with
enemy ships approaching.
This fast-paced, exciting
game offers a variety of
targets. At the end of play,
the game allows you to
enter your name if you have
reached one of the top five
scores. Despite the similari¬
ty of concept to numerous
other games on the market,
this version offers challenge
and excitement. ★ ★ *

For more information, cirde 8 on
reader service card.

which your

planet needs for continued
survival. But the precious
substance is carefully
guarded deep within the
Vault. The Centaurs are
your enemies and they are
ruthless, highly- ski lied
fighters who zealously
guard their Zykon.

There are five levels of
play in this game, each
more difficult than the last.
All levels are extremely dif¬
ficult, and in order to suc¬
cessfully complete your
mission you must conquer
the Centaurs and penetrate
the vault on each successive
level. Vault of the Centaurs
is fast paced and visually
very effective. A cardboard
overlay is included in the
package which puts the six
cursor keys at your finger¬
tips, while covering up the
other keys. If you fancy
yourself to be Jedi material,
then Vault of the Centaurs
is a game you don't want
to miss.

For more information, circle 9 on
reader service card.

Lightning

Tour

80 HOURS AROUND
EUROPE

International Publishing
Software, 16 K
A refreshing change from
space games is 80 Hours
Around Europe,
which takes you on
a whirlwind
tour right
here on
Earth.

The object is
to visit 12
European cities in 80 hours
with 1,500 British ppi^nds,
Sound easy? Wejl^t's pot
You must obtain a souvenir
from each city before you
can travel to the next. Get¬
ting there is tricky for there
are all sorts of unpredic¬
table delays, including los¬
ing money in poker games,
snow drifts, having to bribe
officials, having to return to
the last city in order to
retrieve a forgotten
souvenir.

Upon arrival in each city
you must convert a portion
of your British pounds into
the local currency, then
purchase a souvenir as well
as transportation to the
next city. But buyer beware
because the price for
souvenirs can fluctuate,
which can devastate your
budget. There's no time for
sightseeing in this game
because the clock ticks
away the hours as you con¬
duct your business. The
game is self-explanatory,
loads easily, and is lots of
fun. * * *

For more information, cirde JO on
reader service card.

— Reviews by George
JVfi/Ier, Gary Walker and
M, K. Wilson.

TIMEX SINCLAIR USER

Technical Review

Mixed-Use 4-Pack is a
Mixed Blessing

POWER PACK 1

Timex, 2K

previously Reviewed

Aft tapes are itifc'unfess otherwise noted.

Chessmaster — Chess, Allows you to save unfinished games for taler,
change sides, resign, and choose one ol seven levels of difficulty. Of all
chess programs, our reviewer gave this one top marks. * * * *
intercomputer — Oemolisher. Drop bombs on an increasing mass of
blocks beneath you. Our reviewer called this game a sleeper ★ Vz

intercomputer — Missile Launcher. Target practise. This slow, simple
game does not make good use of its 16K, and allows you to participate
only in the firing of missiles. * ^

International Computers — Galactic Invasion. Choosing the
velocities of your 15 rockets also determines their directions; you fire
them to save Earth from invaders. Also on the tape are three action
games, a solitaire and a drawing program. None are very fast or really
engaging.

international Publishing & Software — Flashcard, In the
classroom, a flashcard has a problem on one side and an answer on the
other. This program lets you input the problems and answers, poses
questions at random, and gives a score at the end.

International Publishing & Software — Galactic Invaders. Seven
alien ships fly over your laser base; when you destroy them, the next
regiment appears. You get to choose the speed. Annoyingly, some of
the aliens take long rests on the ground, but the game is still a must tor
the video game connoisseur. * * *

international Publishing & Software — Home Money Manager.
Lets you keep track of your finances on a monthly basis, then do a
month- by-month or full year balance sheet. Well-documented, well-
conceived, user-friendly. it it it V?

international Publishing & Software — IK Chess. Limited-option
game suitable for beginners on an unexpanded ZX81. Does not allow
cast It ng or en pas sa nt moves . * *

Powerpack 1 contains
four programs. The first, ts
CALC is designed to be a
powerful calculating aid
with ten memory locations,
and full mathematical and
trigonometric function
capability. The next, ts bar
draws elaborate bar graphs
of up to 12 quantities, ts
graph charts polynomials
and ts BANNER provides a
repeating moving headline
on a marquee centered on
your monitor.

Although all four pro¬
grams loaded beautifully, TS
CALC would not run etfen
the suggestion contained in
the printed instructions, TS
bar drew a nice set of bar
graphs and the largest
quantity filled the screen
with smaller quantities be¬
ing relatively shorter, TS
graph reflected the short¬
comings of the graphics
mode; it worked, but the
graph was not smooth — a
fault not of the program —
but of the machine. TS ban¬
ner accepted a lengthy
message (97 characters) and

flashed it repeatedly across
the screen in a graphics
marquee. Though the i n-
structions said to enter a
41 new message, press break,
then cont,” all that did for
me was eliminate the mar¬
quee: the message con¬
tinued, I had to restart the
program to change
messages.

Other available programs
accomplish the aims of
these programs with greater
elegance. However, Power-
pack 1 does it for a 2K ram.
Though TS calc did not
work for me, I found TS bar
and TS graph satisfactory
and TS banner good.

Overall, Powerpack 1 is a
useful product. I’m sure TS
CALC (if working) could be
useful in some specialized
way, TS BAR produces fine
bar graphs, and ts graph
plots algebraic expressions
satisfactorily — something
Tve wished for every day
since high school! TS ban¬
ner does its job well. **

For more in/ormation, circle 11 on
reader service card.

tnternationai Publishing & Software — Packrabbit Fast-action
maze game with a choice of six mazes. You are a rabbit chased through
a earrotpatch by tour hunters, and must eat carrots to gain points.
When you eat one of the magical carrots, the hunters become edible.
(Note; for a limited time, all new subscribers to TSU will receive this
game as a subscription bonus . ) ***'/?

International Publishing & Software — 2K Chess. Allows castling
and en passant moves but will not let you change sides, resign, or save
a game for later. Suitable for intermediate players using an unexpanded
T/S1Q0Q. +*V*

International Publishing & Software — It Assembler Occupies
7K at the top of the memory. Programming in machine language is
much more difficult than in basic, but programs such as this offer aid by
allowing you to enter and edit machine language using mnemonics.
With the clear, detailed, 26-page manual and a good book on Z8Q
machine language, a beginner will find this program easy to

if it it Vi

International Publishing & Software — It Scramble. Hit enemy
installations before they hit you, while maneuvering to avoid crashing
into treacherous terrain. The game is slow, and the terrain repeats itself
like a chase scene in a poorly animated cartoon . * *

Melbourne House — Combat Flight, Fly through mountainous terrain
and shoot at alien ships. An unexceptional invaders-type game. ★ *
Melbourne House — 30 Monster Maze Evade Tyrannosaurus Rex in a
huge, realistic maze - not too difficult, since Rex is a touch sluggish,
which tends to slow what should be a fast , exciting race. ★ it

Melbourne House — 3D-0rbfter As they approach, the alien ships
grow and display increasingly fine detail; when you shoot them, they
explode with wonderful realism. Besides the superb visuals, this game
is very exciting and will provide hours of fun. * * * *

Mindware — Cosmos. Avoid hitting your own convoy and alien space
mines as you fly through space looking for alien ships to destroy. Fast,
fun and challenging. * * *

Mind ware — The Fast One. A ‘computerized filing cabinet/* Ideal lor
setting up lists of phone numbers, recipes, addresses, inventories, and
any other listable information. Excellent documentation. it it it Vi
Mindware — Gulp. You move around any of six mazes at any of nine

TIMEX SINCLAIR USER

speeds eating dots while a hunter pursues you. The keys that control
movement are too dose together, and after you eat the last dot you have
to be captured before the game ends, but it's still enjoyable. ★★★
Mindware — Labyrinth Vou may choose to see an overview of the com-
piex, 3D- style maze before you wander through it, and if you get lost
and give up you get to see the whole picture again. With practise, the
trek becomes simpler. An interesting game but not a classic.

Mindware — Multiple Choice This so-called ' educational'' program
asks questions like “What is the capital of hie w York slate?" and
“What is the square root of 2?” but isn't really anything more than an
information drill. As such it works well, though, and lets you create
tests of your own **★

Mindware — Pilot Land a small aircraft using 12 keys to control direc¬
tion, flap and landing gear, and speed of climb and descent. Realistic
cockpit meters display air speed , altitude, fuel, distance to the runway,
and so on. Landing is difficult but you can always switch to automatic
pilot. * * V?

Or byte Software — Home Budget Its 39 categories (which you can
alter) help you organize your spending habits. After analyzing proposed
and real budgets, this program compares them in graph form; and
despite poor documentation , does a good job . ★ * *

Ozdyte Software — Mega Mind Addictive game similar to Master-
mind, using shapes instead of numbers. Guess what shape is where:
the computer tells you the number of shapes in the right and wrong

posi t ion , ieav i ng you to shift them. Fi ve I eve! s of d i ff i culty . *

Quick sitva — Munchees From one to four ghosts (you get to choose)
chase you around a well-constructed maze, The movement keys are too
close together, causing difficulty at high speeds, but this game is still
fun to play - repeatedly . ★ * *

Reston Publishing — Invasion Force Shoot lasers through a moving
force field to destroy alien ships, and watch out for bombs. The game is
fun, the graphics distinctive. ★

Reston Publishing — Math Series This full-fledged math program is
divided into six sets corresponding to grades one to six, each with 32
lessons, a 64- page workbook, a vinyl storage case, and a hefty
pricetag,

SoftSync — Computer Tutor This series includes Math Raiders and
Alpha/ Vowel Tutor, which really don't teach, but rather ask questions
and correct wrong answers, For fun, it rates high; for educational
value, it rates low.

SoftSync — The Financial Manager and Record Keeper. This well-
designed program has 19 categories to help you keep track of your
dollars— tells you what per cent of your income each of your expenses
constitutes, and makes other sundry financial calculations. A good
budget planner, ***

Softsync — Graphics Kit. Offers 23 machine language routines and a
variety of sophisticated graphics devices like R evers e and border. If
every Timex retailer used this as a demonstrator, sales would soar.
Doc umen tat ion poor . * * ★

SoftSync — Night Gunner You are the pilot ot an airplane in an aerial
dogfight with four others, and must shoot them down before they shoot
you. The game is fun, the action fast, the graphics not
outstanding,

SoftSync — Star blaster. One of a six-pack of 2K games marred by poor
instructions but enjoyable for those who own machines with unexpand¬
ed memories * *

SoftSync — TS Destroyer and Space Raid Fast action duo in 2K, In TS
Destroyer, you must dodge or destroy floating objects as a spaceship
takes potshots at you; in Space Raid, you must shoot a hole through a
spaceship and hit the left foot of an alien. Neither game prints a
score*

SoftSync — Superchess, Plays a mean game at ten different levels of
difficulty. Recommends moves, plays itself, but doesn't let you save
games for later. Packaging adequate but not great . * * * Va

Thomas 8. Woods — ZX Data Finder This storage and retrieval
system offers some very advanced title and word search features, and
helps you keep track of everything from correspondence to car repairs.
Comes with a complete listing and a thorough explanation. * * * *
Timeware — Chess Offers six levels of play, recommends moves,
allows you to save u nfinished games for later but not to resign . * * *
Timex — Ator, the ABC Gator Eye-catching graphics, great pacing, and
sound make this educational tape of great value to children just learn¬
ing their ABCs. An adult is needed to synchronize the sound with the
vi sua Is and t o he I p t he yo u ngster read the i nst ruct ions . * * * 'h

Timex — Chess Doesn't recommend moves, play itself, change sides or
allow you to save or print games . Otters six levels of difficulty. * * *
Timex — The Coupon Manager Before you go shopping, you can flip
through your tile of coupons and pick out the ones you need. Keeps
track of amount, store and expiry date. A must for the compulsively
organized, ♦**

Timex — The Cube Game. A computerized variation of Rubik's Cube,
Choose a solid, unfolded two-dimensional or see-through three-
dimensional cube, then move blocks by specifying axes The
movements are slow, the graphics good — once you get used to
them. ★★

Timex — Flight Simulation Land your plane successfully on the runway,
taking flying speed, wind speed, attitude, fuel and other variables into
account . You win by not crashing . * * * *

Timex — Mixed Game Bag 1. Bowling gives you ten frames of IQ-pin;
you control the ball s direction with the up and down arrows. Bingo
gives you a card, a series of random numbers, and the opportunity to
cheat by not verifying your claim of Bingo. Robot Wars is a humorously
visual version of Mastermind, and the best game in this well-rounded
package ***

ZX-Panding — Checkbook, Tax and Budget Organizer Helps you
manage your finances. Comes with a clear, four-page booklet but gives
no clear instructions on how to get going after loading. An excellent
save frame lets you return to the menu in case of error . * * *

9/0

AN “EARLY-BIRD” CHRISTMAS SUBSCRIPTION GIFT OFFER

>\ \ '//

Timex Sinclair User at $1.66 per issue!

Too early to think about Christmas gifts? We don't think so! In
fact, by thinking about them now you can save yourself some last-
minute shopping headaches and some money. From now until
November 1, 1983, we are offering a special Christmas gift
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one full year’s subscription, to Timex Sinclair User{ Only $1.66 per
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TIMEX SINCLAIR USER
f SPECIAL CHRISTMAS OFFER
j 49 LaSalle Avenue
Buffalo, N.Y. 14214

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TWO QUESTIONS

Letters

elements of one or more strings,)
On other large units, there are com¬
mands which save it, but how can I
do this on my ZX81?

Steven Bottoms
Lampoc, California

Can you answer these questions for
me please?

(1) What is the largest number the
ZX81 stores as an integer?

(2) 1 would like to use my ZX81 as
a remote terminal to connect with a
mainframe but the mainframe re¬
quires a @ before all system com¬
mands and the ZX81 does not have
a Is there any way around this
problem?

Ronny Richardson

Chamblee, Georgia

The ZX81 stores integers as eight
significant figures (four bytes) and a
one byte exponent + 38, ie, 9999999
or 9,9999 999 + 38 ,

About the @ — it is 40H ascii
which is 64 in the decimal system.
All your data would have to be con¬
verted into ASCII since this is the
language most mainframes use. A
short machine code program could
do this. You could do it in BASIC but
it would be very slow. In your
machine code program you would
redefine the keyboard and then
establish a link with the mainframe
by developing a new set of control
characters. If you need some more
information, )ust write to us again.
Good luck with your Jink!

COMPATIBILITY

Will the solid-state mini-cartridges
and interface for the T/S150G be
compatible with the T/S 1000?

Also, what exactly is a
microdrive? And is it compatible
with the T/S 1000?

Terry Marshall

Kansas City, Missouri

The mini-cartridges will not plug in¬
to the T/SlOOO. However, if you save
the software from the cartridge to a
tape, the program will work. Also,
all software for the TISiOOO will be
compatible with the T/S 1500 since
the T/S 1500 accepts both tape and
cartridges.

A microdrive is a small disk drive
which speeds up the loading and

saving of programs as well as in¬
creasing reliability. You should
check with the manufacturer regar¬
ding its compatibility with the
T/S 1000.

REMARKABLE

How do I save specific bytes of
memory?

John Schmitt

Aylmer, Ontario, Canada

The best way to save machine
language is to store it in a REM state¬
ment at the beginning of a program.
For example, if your routine is ten
bytes long, make your first state¬
ment:

1 REM XXXXXXXXXX
The ten xs will reserve ten bytes
starting at address 16516, Now poke
your machine language into these
ten bytes. TheXs will change to dif¬
ferent characters.

You can now save your routine
and run it with RAND U5R 16516
statement.

DIFFICULT SAVES

1 have a difficult problem that
possibly can’t be solved on the
T/S 1000, ZX81, 1 need to save a par¬
ticular block of memory on tape, to
be loaded for future reference or
use. (Example: Save locations
22500 to 27600; locations contain

The save always starts at the begin¬
ning of the BASIC area. There is no
easy way to save a particular block
of memory unless the block starts at
the beginning of basic. Some special
pieces of software have been
developed to help with this problem.

TECHNICAL NOTE

Regarding your In-Depth article
of issue No. 1, “Inside the T/S 1000,
ZX81," it is worth mentioning that
the photo on page 43 is not
necessarily what a T/SIQQG, ZX81
owner will find upon opening up
his or her computer. The ZX81 is a
five chip board with RAM locations
4a and 4b, so there will be two
smaller chips at the right, and the
CPU is nearest to them, followed by
the ROM and then the ULA, Pur¬
chasers of the T/S1000 at $99
received the next step, which is a
ZX81 board with the two RAM area
ics removed and the 2016 static
chip (2K ram) replacing them.
More importantly, the $99 board is
socketed, so all chips are therefore
easily removable (using an IC
puller/replacer) for troubleshooting
and replacement, while the newer
and cheaper version in the photo
mentioned has soldered-in-place
ICs which cannot be readily servic¬
ed, Maybe Timex will offer a CPU
card for this purpose? Otherwise

TIMEX SINCLAIR USER

i _ _ _ _

the new board is much neater in
layout and more professional in ap¬
pearance than the older ZX81
boards.

Also* an Atari or Atari-
compatible joystick may be attach¬
ed for those games where locating
the key while watching the screen
tends to take away from the fun.

Several options are available, all
cheap and fairly easy to perform.

For the sake of being neat I chose
to install a plug for the joystick. The
connection could be made direct if
so desired, however. If direct, cut
the plug end off the joystick cable
and use the color codes. If a plug is
installed, refer to the numbers em¬

bossed on the plug or to the
diagram. To use keys B-6-7-8 as up-
down-right-left is not possible with
this method, however 6-7-8-9-0 is;
and turns out to be a good alter¬
native. 6, 7 and 8 are used for the
same directions as indicated by the
arrows on the keyboard; 9 is
substituted for 5; and 0 is used for
fire control.

Connections to Sinclair KB ports:

DE9P No.

Color

Keyboard

Code

connector

Black

Blue

White

Brown

Green

Orange

Using the joystick has the same
result as if the related key were
depressed; so the software requires
writing for keys “6”, “7”, “8”, "9”,
"0P\ As an example, in the Laser
Cannon listing in issue Number 2,
change line 130 from if inkeys = "8”
to if inkey$ = "0’\,« and line 140
from IF lNKEY$>t<5t,**» to IF IN-
key$> = and line 190 change
*‘8P# to This enables key 0 as
fire control so movement and fire is
the same as an Atari (control). The
drawback is that machine code pro¬
grams such as Flight Simulator are
not as easily changed (it requires
substituting the 9 key for the 5 key
in machine code instructions).

The DE9P costs under $2 and the
Atari joysticks range from $7 to $25
dependent upon manufacture and
model. I used the controller that
came with my VCS (2600) and it
works just fine.

Ed Pardo

Hopatcong* N,J.

TAPE RECORDER BLUES

I will be more than happy to
subscribe to your magazine if you
can find a tape recorder that will
LOAD. If you can get me a tape
player that is guaranteed to work, I
will even buy it from you*

Carlin S* Champlin
Brockport, Pennsylvania

Cariin, we're both in luck. We get
you to subscribe and you get to use a
continued art page 46

TIMEX SINCLAIR USER
CHRISTMAS SHOPPER’S GUIDE

Free in our December Issue

The December issue of Timex Sinclair User
magazine will feature a Christmas Shopper’s Guide
as a special “pull-out” section. This mini-magazine
within a magazine will help you with your Christmas
shopping. A gift for every T/S user on your list.

FEATURES:

* Hardware, software, & books listed by company
and price

* Description of many of the items listed

* Addresses and phone numbers of suppliers

* Special Christmas program printout

WATCH FOR IT!

On Sale November 15!

TIMEX SINCLAIR USER
Free in the December issue
Christmas Shopper’s Guide
Special Mini-Magazine

* What software to buy

* What’s new for T/S users

* Where you can buy it

* How much does it cost

* Gift suggestions for every T/S user on
your list

TIMEX SINCLAIR USER

Can Timex maintain its image
of clocklike efficiency?

OVER THE YEARS, Timex came to be viewed
as a company that knew how to develop and
market modern technology at affordable
prices. We saw a smooth-running, dependable,
always-come-up-ticking operation. It came as a sur¬
prise — no, a shock — for us to realize that Timex too
is fallible. It is run by people and it is run for profit.
Neither of these things is bad, it's just that we forgot
them. Timex’s clock-like business belied the facts
beneath the organization.

As in all organizations that are on top for so long,
small mistakes can be glossed over. The corporation
can absorb many knocks, especially those delivered
from within by well-meaning executives. No one
decision, no one person, no one step suddenly
causes the giant to falter, but a series of mis-

judgments, unavoidable problems and technical dif¬
ficulties seem to come together at one juncture,
Timex Computer Corporation appeared at one of
those junctures. That the company and the computer
weathered the crossroads is solid testimony to the
health of both. Still, we at Timex Sinclair User, who
wish nothing but health and success for Timex, feel
the company should take a collective breath, regain
its cool and take up where it left off ... at the top!
Build on its past success formula; modern
technology at consumer price levels.

The new T/S15O0 and T/S2068 are excellent
machines. So much so that there is talk in the U.K. of
importing them (the parent outstripped by its off¬
spring). We hope that Timex presents these
machines in a light that allows the public to see just
how great they are.

Timex is a strong company! The T/S1500 and
T/S2068 are strong computers! Let’s have a show of
strength from Timex Computer Corporation!

Inside this month

Many early enthusiasts of the T/Sl000,ZX81 set up
active and exciting user groups. From these groups
have emerged many small companies. This is a

superb example of the strength of the North
American entrepreneurial system. Henry April of
the Boston Computer Society is now the owner of
E-Z Key, a company that designs and produces add¬
ons for Timex computers. In this issue, the Penn¬
sylvania User Group is featured. Bill Russell, who
develops and markets many products for the Timex
line, including the Winky Board 2, was one of the
founders of this group. We would like to feature
more people who have moved from enthusiast to en¬
trepreneur. Write to us about your experiences or
those of someone you know.

Color on your T/SlGQG,150QtZX81? Yes sir! Our
feature project this month shows you how to build
just such a colorboard. You can use this device to
generate color from your black and white computer.
Of course, you will need a color television, but as the
saying goes, in order to see through rose-colored
glasses, you need to have rose-colored lenses!

Our Kingdom For A Subroutine

Astute readers will remember that one of our Pro¬
gram Printouts this month, Kingdom, ran, minus
about a dozen lines, in Issue #3. Numerous readers
told us of the problem, “You blew it last issue!’1
wrote Mike Potter of Frankfort, Illinois. “Kingdom
looks like it could be a very good game if I could
figure it out,” said Robert Keneely of Kew Gardens,
New York. David A. Hartmann of St. Ann, Missouri
told us: “It was very ironic that the same issue you
did a story on ’Software Blues’ . . . My compliments
to Andrew Johnson for an otherwise fine program.”
Kingdom is a fine program, Andrew, and we
apologize to you and our readers for botching it. It’s
worth another try.

As John Gilbert’s five part series on programming
ends, we are excited to introduce a new series, Pro¬
gramming Arcade Games. This set of articles is
taken from the yet-to-be- released book of the same
name From Reston Publishing of Reston, Virginia. In
this series, our own Bob Fraser (programmer turned
author) leads on from where Gilbert left off to show
you special ways to get arcade-like games from your
computer.

All in all, a special issue! As usual, if you have any
special thoughts or ideas, programs or print-outs,
kudos or complaints, let us hear them,

• Write to Timex Sinclair User, 49 La Salle Avenue,
Buffalo, N.Y. 34214-1414,

TIMEX SINCLAIR USER

Home Computers Can Make
You Rich, by Joe Weisbecker
(Hayden* $7.95)

WEISBECKER’S BOOK is
full of ideas on how to turn
your spare time and your
interest in computers into dollars.
You don’t have to own a computer
to appreciate this book, or like com¬
puters* but it helps.

Home Computers Can Make You
Rich gives us a very short course in
business procedures, in which such
topics as money-making principles*
trend-watching, and possible pit-
falls are discussed, Weisbecker en¬
courages us to make money “for
Fun and profit1* in our spare time
and assures us that it is "easy to
do.” We are introduced to our

potential customers: “hardware-
hackers” (those who play with cir¬
cuit boards* electronic gadgets,
design and build kits, and so on).

Turn your bits
and bytes into
dollars and cents

technicians, engineers* repairper¬
sons* and other computer en¬
thusiasts.

This is essentially an ‘idea1 book.
There are many interesting ideas

presented that could be developed
into a supplementary income* but
these would prove financially
worthwhile only after much careful
thought and planning. Weisbecker
makes his money-making ideas
seem easy, and downplays the time*
skill, and business acumen required
to commit his (or your) ideas to
reality and actually have them pay
off. His message is clearly op¬
timistic: "You can do it."

Among the potential money¬
making ideas presented are writing
articles for various publications*
writing a newsletter, writing a
book, creating and selling pro¬
grams, becoming a computer con¬
sultant or repairperson, or renting
out computers by the day or week.
There are some novel ideas too,
such as using your computer to
entertain at parties; for childrens*
parties* you’ll also need a funny hat
and costume.

Available from Hayden, Home
Computers Can Make You Rich may
well be the motivational boost you
need to get your ideas off the
ground and start turning your bits
and bytes into dollars and cents.

— M.K. Wilson

The Microchip
Demystified

Mastering Machine Code On Your Timex/Sinclair

by Toni Baker
(Reston, $18,95]

BASIC is a good language. In
fact, it's more than ade¬
quate for most applica¬
tions, especially if you’re new to
programming. But where does one
turn to satisfy the cravings for
mega-fast number crunching or
lightning-quick graphics? The
answer lies in machine language
programming.

Toni Baker’s Mastering Machine
Code on Your Timex/Sinclair is in
essence a step-by-step tutorial on

how the Z8G microchip works.
Machine code is the Timex’s native
language* while BASIC is a bilingual
guide. Learning machine code
eliminates this need for translation
and the time it takes. The result is a
computer program that runs more
efficiently and, therefore, faster.
One of the first chapters clears
the air about computers and their
hexadecimal number systems. For
instance* did you know that the
T/SlOO0,ZX81 and all other per¬

sonal computers use a base-16
number system? Baker tells how to
make the transition from our more
commonly used base ten to hexa¬
decimal and back again.

The other chapters are filled with
hands-on programming applica¬
tions: the reader learns by doing.
Imagine experimenting with
graphics and music mixed in with
your game creations. Yes, music
from the Timex! Baker ignored the
systems design and went on to
figure a way to make music using
machine code.

Programs include: Graffitti*
Draughts (Checkers), Spirals and
other games. Especially useful are
the De-bugging and Dis-Assembler
utilities. This text is must reading
for anyone wanting to learn to fine
tune their programs.

— Tim Banse

TIMEX SINCLAIR USER

Disassembly book
is complex,
invaluable

The Complete Timex TSlOdO/Sinciair ZX81 ROM Disassembly,
Parts A Sr B, by Dr. Jan Logan and Dr. Frank O'Hara
(Melbourne House, $19.95)

WHEN Dr, Logan says com¬
plete, he means it. This
compilation of two
volumes (previously sold separate¬
ly) provides the serious machine
code programmer with an annotat¬
ed disassembly of the monitor pro¬
gram from one end to the other.
The first part, up to memory ad¬
dress OF54 (hex), does not have line
by line comments as does the se¬
cond, possibly due to O'Hara's in¬
fluence. Though these comments
would have been nice in the first
part, they are not essential, since
the subroutines are generally less
complex than those in the second,
which deal mainly with floating
point mathematical operations.
Both sections, however, have

'nciud.

tyDt

& Fra.

'an Logon H'1DffH
'nfc O'Haro

bit complicated to the beginner,
and rightly so, since the book is no
piece of cake for advanced pro¬
grammers either.

The complexity does not come
from Logan (who has done an

Amazingly, in decoding the monitor
program, Logan did not consult with
the Sinclair organization

simplified flow-charts and break
down the program into individual
subroutines that are titled and in¬
dexed by the authors. All entries
and exits are labeled as well as ad¬
dressed in hexadecimal. Tables are
also included with indicators and
comments when necessary. The ap¬
pendix contains five short BASIC
programs that illustrate how SIN,
EXP, ln and ATN functions work in
the monitor using Chebyshnev
polynomials. This might all sound a

amazing job), but from the original
programmers who crammed the
program into eight kilobytes of
ROM, unconcerned about its
readability. As O'Hara indicates at
the beginning of Section 2, the
feat is doubly amazing considering
that Logan did not consult with the
Sinclair organization to decode the
program. It seems that he reads
assembly language like we read
magazine articles.

This book is in a class of its own.

Many volumes deal with the Z80
microprocessor and assembly
language in general, and several
relate these directly to the
T/S1000,ZX81, sometimes supply¬
ing machine code and assembly
routines of questionable quality
and usability. Books specifically
devoted to your computer are
usually the most helpful, since you
can apply the information con¬
cretely. Drs. Logan's and O'Hara's
work provides hundreds of proven
subroutines that you may access
directly, recopy and alter in RAM,
or simply learn from.

If this book seems difficult to
assimilate, it's because there's so
much to learn from it. If you are a
beginner and serious about
machine language programming,
don't wait until you are advanced
to get this disassembly; you may
wait a long time. Since you’ll have
to learn assembly sooner or later,
why not start with the original pro¬
gram in the Sinclair ROM? 0/ 0
— Andr£ RoussiJ

TIMEX SINCLAIR USER

ILLUSTRATION * Don KJetke

Inventor Jim Stephens shows how to build
a colorboard for only $62

Convert your T/S,ZX to Color

OKAY, so Ill admit my little
ZX61 has a few shortcom¬
ings. Some of these I can
live with. Some I had to change.

My computer games were con¬
stantly being criticized by my two
sons, who reminded me daily that

so-and-so’s computer had color
games. Well, 1 added color to my
T/S1500,1000,ZX81 and got four
extra pages of memory in the pro¬
cess. Let’s see old so-and-so top
that.

Now my games have an extra tint

of realism, my charts are clearer
and my neighbor is somewhat less
smug.

The colorboard is not a simple
project and should be undertaken
only by persons with a lot of pa¬
tience and experience in kit-

TIMEX SINCLAIR USER

building* The builder should
understand that there are a few
limitations, and the use of the board
is sometimes awkward unless
sophisticated software is written to
handle the board's operation* The
project is presented mainly as a
learning experience, and proper
operation will ensure an increased
knowledge of computer electronics
and how data is manipulated and
used for purposes other than
number crunching.

How the Colorboard Operates

The T/S,ZX colorboard is built
around a super chip called the
MC6B47 Video Display Generator
(vdg) and its companion chip, the
MC1372 Color Modulator, Don't let
these fancy names scare you. These
chips are readily available through
most parts supply houses or can be
ordered from Motorola* Many of
the mail order suppliers also stock
these. The 6847 is a 40-pin MOS chip
that has the ability to display a 64
element ASCII character set, up to
256 x 192 graphic pixels and eight

Warning:

the colorboard is not
a simple project,
and requires patience
and experience

colors. The high resolution,
however, requires 6K of memory so
I limited my matrix to 128 x 64 us¬
ing only IK of video ram (vramj*
The connections in Figure 1 show
how the wide range of modes are
handled by the various connec¬
tions* For example, if the board is
wired as in Figure 2, a data word of
1000 0010 or 130 decimal would
produce a color quarter pixel in
green. Changing the data bits in the
word changes either the
alphanumeric character, color or
shape of the pixel* Figure 3 shows
the decimal numbers for each of the
alphanumeric characters and
graphic shapes* The colors are
changed depending on the value of
the three most significant bits in the

word* If a higher resolution is
desired, and only graphics are
needed, then a resolution of 128 x
64 can be obtained by wiring the
mode select lines as shown by line
eight of Figure 1.

As you can see, the various
modes and capabilities of the 6847
can be readily handled by software.
With the use of machine code, a
great game of super breakout can
be achieved, and in color!

Video Circuit Operation

The block diagram in Figure 4
will give you an idea of the various
data paths and how information is
routed to produce the display. The
VDG constantly scans the IK of
VRAM with its address lines and
samples each location and reads
the stored data* This information is
read into the VDG and is output as
raw video to the 1372 color
modulator. The 1372 circuit im¬
presses the video data onto its rf
output which is then fed directly to
the television antenna terminals*
The video signal from the T/S.ZX is

Mode Selection of the 6847 VDG *

GRND

CSS

A/G

A/S

CHB

INV

clkB

I NT/EXT

clkA

GM0

GM1

GM2

■

+ 5v

A1Q

All

A12

MC6847 Pin Locaiions-Top View

Figure 1

VDG pins

output of VDG required memory

AIG

A/S INTI-

E XT INV GM2 CMl

GMO

X X

64 ASCII Characters

1/2K

X X

same but inverted

1/2K

- +

X X

external ROM capability

1/2K

- +

X X

some but inverted

1/2K

X X

8 colors-Alpha/graphicsf64x32j

H2K

+ +

X X

4 coJors‘A/pha/graphicsf88x48J

1I2K

X X

4 color graphics (64x64j

X x

2 color graphics (I28x64j

X X

- +

4 color graphics f 128x641

2 K

X X

* +

2 color graphics (128x961

X X

4 color graphics (I28x96j

X X

2 color graphics (128x192)

X X

+ +

4 color graphics (128x292J

X X

+ +

2 color graphics (256xl92j

Note: f-j

“ ground, ( +

j “ 5 volts and (xj

- don't care

* Source; Specification sheet no. ADI-492 R2 Motorola Semiconductors* Austin* Texas.

Component side

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Underside

Pinout of backplane on T/S.ZX showing the corresponding connections

TIMEX SINCLAIR USER

Curvets’

obtained as shown in Figure 5,
which provides the T/S,ZX data to
the newly constructed modulator.
If a color video monitor is used (an
expensive item), the 1372 circuit
can be eliminated entirely.

The video circuit is basically a
stand-alone system which con¬
tinuously outputs color data to the
screen. The problem occurs when
the data in the vram has to be
changed. If the constantly changing
address and data lines of the VDG
were put directly on the buss of the
T/SlSQO.lOOO^XSl, complete
havoc would result, A method must
be devised to shut off the vdg, open
the buss to the computer, read or
write into the IK, and then discon¬
nect the buss in order for the VDG to
continue its operation. All of this
must be done quickly and orderly to
avoid screen flicker. It is not an
easy task, but much simpler than
you would think.

The Interface

Of all the exotic interfacing
chips, two of the most simple are
the 74LS157 Quad2-Line to 1-Line
Data Selector/Multiplexer and the
CMOS 4066 Quad Bilateral Switch,
These long names simply mean that
they are electronic switches that
connect and disconnect the buss
lines at the proper time. This pro¬
cedure is called "mult flexing.”
Since there are two different busses
with different characteristics, two
types of multiplexing will be
necessary for proper operation.

FT O—

“J

If "I

-h

“

\ f

tSv

k /

\ /

-,TVL-y

Figure 2, Circuit diagram.

Address Multiplexing

The address buss accepts its data
in only one direction. That is, the
direction of flow is always to the
device, never /rom it. The 74LS157
accepts two inputs from two dif¬
ferent sources and outputs either
one or the other depending on the
state of the select pin. A low on this
pin in Figure 2 would route the ad¬
dress information from the T/S,ZX
buss to the VRAM and cut off the
VDG address lines. A high on the
select pin would let the VDG scan
the VRAM and would disconnect the
T/S,ZX,

Data Multiplexing

Since the data buss transfers data
information in two directions, the
CMOS 4066 analog switch was
chosen. This 14-pin chip contains
four separate line switches which
effectively connect and disconnect
the data lines going to the VRAM
from the computer buss. A high on
the control pins, 5, 6, 12 and 13 will
allow four bits of data information
to pass into and out of the IK of
VRAM, A low on the control pins
disconnects the VRAM from the
computer but allows the VDG access
to the data stream. Two of these

chips control the entire eight bit
data buss.

Interfacing the VDG to the
Computer

Even though we are taking the
computer off the VRAM buss, the
VDG is still trying to read the data
and still routing information to the
modulator. Pin 12 of the VDG is the
chip select pin that shuts down the
6847 when that_pin is brought to a
low state. The CE pins of the eight
2102 ram chips are permanently
enabled by being wired directly to
ground. Therefore, they are either

TIMEX SINCLAIR USER

reading or writing depending on
the state of the WJme of the
memory chips. This W line is en¬
abled when the MWR is brought low
for a write operation. Otherwise it
remains high controlled by one sec*
tion of a 74LS157 so that the VDG
has it ready for reading at any time.

The real problem is in getting the
T/S,ZX to coordinate all of this ac-
tivity in a usable fashion. The ZBO
CPU has several methods to ac¬
complish this. There are two major
ways in which the Z80 accesses
memory or any external device.
One is called the I/O Port Method

where the device select number is
generated by the eight low address
lines. Our method is the memory
map technique. This method is
much simpler since we are basical¬
ly using ram as the external device.

Memory Mapping the Video RAM

In order to generate a pulse that
will activate all of the multiplexing
circuits, a 74LS138 three-to-eight
line decoder is used. This little
16-pin chip will generate a low
pulse when the selected address
lines become valid. If a write to
memory is sent from the CPU,

several things happen on the buss
that give us the signals to control
the address and data switches. First
the CPU puts the address informa¬
tion on the buss in response to a
write command. Then, the MREQ
line goes low. The MWR goes low
and the mrd remains high. The pro¬
per use of the signals along with the
address lines enable us to control
the multiplexers in a coordinated
fashion. This is called interfacing.

The 74LS138 has three chip
enable pins and three data pins. A
high on pin four or five or a low on
pin six will disable the chip. Since
the address lines of the Z80 CPU are
active high, and MREQ is active low,
a chip enable can be obtained with
address line 15 on pin six, MREQ on
pin five and address line 13 on pin
four. Address lines A10 through 12
go to pins one through three. This
gives a memory request pulse for
addresses 36,864 through 45,056
depending on the number on lines
A10 through A12. It is this pulse
that controls our interface chips for
the most part. I selected address
37,888 as the starting address of the
IK VRAM simply because it was
easy to remember. The address
pulse for this IK is output on pin 10
of the 74LS138. This control pulse
is used as the enable pulse for the
address multiplexers and is com¬
bined with MRD through a NOR gate
to open the 4066* s which gate the
vram data onto the computer's
data buss.

If more than 16K of RAM is being
used, it is quite possible to mount
the board into the unused 8K area
above the system ROM. The connec¬
tions at the 74LS38 would need on¬
ly minor revisions. This modifica¬
tion would give you the ability to
run machine code from the video
RAM.

Although it is not absolutely
necessary, all lines are buffered
with CMOS 4050 non-inverting buf¬
fers. These buffers will give the
signals more drive but, more impor¬
tantly, will give a little extra protec¬
tion to the CPU in the event of a wir¬
ing error. The 4066s are the buffers
for the data lines.

TIMEX SINCLAIR USER

XmNCS

ZX KEYBOARD FOR USE WITH 80/81 SPECTRUM

Our new cased keyboard has 52 keys, 12 of these are used for the numeric pad The numeric pad offers some useful features, you can cursor with
one hand and rt will be a boon for anyone who enters a lot of numeric data The pad is a repeat of the f -9 keys plus rt has a full stop and a shift key. The
numeric pad keys are coloured in red, the normal keyboard keys are grey, with the case being black which makes the whole thing very attractive. The
case measures 15 x 9 x IVi The computer (either 80/81 or spectrum) fits neatly inside You will have to remove the computer from its original case, it is
then screwed to the base of the case The case had all the bosses already fitted and the screw holes are marked. Also fitted inside the case is a mother
board [81 model only) which allows 16K, 32K and 64 K to be fitted in the case. All the connections are at the rear of the case i.e Power, Mic, Ear. T V.
and the expansion port The case is large enough for other add ons also
to be fitted inside One of these could be the power supply, then you
could very guickly fit a mains switch, or a switch on the 9V line This
means you have a very smart self-contained unit This case does not
stop you from using any other add-ons that you may have e g Printer
etc We are convinced that this is the best keyboard available at
present, It offers more keys and features than any other keyboard in its
price range

NOTE

The case can be purchased separately with the keyboard aperture
uncut, so if you have one of our early uncased keyboards, or m fact any
other suppliers' keyboards, these could be fitted The keyboard is
connected to your computer by a ribbon cable and this has connectors
fitted which simply push into the Sinclair connectors ft is a simple two
minute job and requires no electronic skills This keyboard does not
need any soldering Please specify on order whether you require the ZX
8f or Spectrumcase

SPECTRUM MODEL

This is supplied with spectrum legends, and a slightly different base
for fitting the spectrum inside, again all the connectors are at the rear of
the case and there is plenty of room for the power supply (and other
add-ons] Shoukl you want to change we can supply both the
Spectrum legends and details of updating your case which will enable
modification from the ZX 81 to spectrum PLEASE specify on your order
whether you require the ZX 81 or spectrum case

KEYBOARD
(SPECTRUM/81)

Internal fixing for
ZX 81 keyboard case.

r - “ T

* POW B *
I&4JPPLT i
RAM

Internal fixing for
spectrum keyboard
case.

SPECTRUM LIGHT PEN

The pen enables
you to produce high
resolution drawings
on your own televi¬
sion set, saving a vast
amount of time over
using basic program¬
ming statements, such
as Plot. Draw etc You
can erase, modify and
save drawings and rt
comes complete with
software program.
The superb light pen is
available from DK
tronics

$49.95

SPECTK

I6K Memory E>

The 16Kuses41U
Static Ram and oc
using the Static R
speed low power
the comparer. A
which comes to j
where. Position ii

64K Memory Ei

All the above inf
advantage lies rn
56K of usable me
the use of other <
8 192-65536. The
Spectrum Memi
Upgrade your Spi
it rs simply slipped
are supplied, and
time, The fitting r
same as Sinclair’s

ZX 80-81 Spectrum

HARDWARE

SPECTRUM/81 TOOLKIT

This is the toolkit which won acclaim in the feature in the August
1982 issue (pages 29 and 30] of Sinclair User. "It is the tost impressive
program, fast in execution with clear and full instructions., it stands out
from the rest of the field." The ZXED is a powerful editor for use on the
expanded ZX81 , ft is intended for use by the senous BASIC programmer
and offers several useful and time saving features most helpful during all
stages of program development. The facilities provided are as follows;
ALTER, BYTES, COPY, DELETE, FIND, HELP, INSERT, KEEP, MOVE,
RENUMBER AND VERIFY The Spectrum Toolkit contains most of the
features above plus autofme numberer and append, and will run in the
16K and 48K spectrum.

Both at
only $12.95

FLEXIBLE

CONNECTOR

ff you have ever had whiteouts
or system crashes this could be
the answer. It stops the move¬
ment between the computer and
the RAM expansion, it is supplied
with a ribbon, 6 inches long, with
a male connector at one end and
a female at the other, at only

$35.95

4K GRAPHICS ROM $44.95

The DK Graphic module is our latest ZX 81 accessory This module
unlike most other accessories fits neatly inside your computer under the
keyboard. The module comes ready built, fully tested and complete
with a 4K graphic ROM This will give you an unbelievable 448 extra
pre-programmed graphics, your normal graphic set contains only 64
This means that you now have 512 graphics and with their inverse
1024 This now turns the 81 into a very powerful computer with a
graphic set rarely found on larger more expensive machines, In the
ROM are lower case letters, bombs, bullets, rockets, tanks, a complete
set of invaders graphics and that only accounts for about SO of them,
there are still about 400 left [that may give you an idea as to the scope of
the new ROM] However, the module does not finish there, it also has a
spare holder on the board which will accept a further 4K of ROM/RAM
This holder can be fitted with a 1K/2K/RAM and can be used for user
definable graphics so you can create your own custom character sets

WHY WAIT?

ORDER TODAY FOR FAST DEU VERY

T6K Memory $41.95
1 0K juncAMrf] »/f «
64K Memory if J5 0O
&4K |unc*£fd| $132-00

16/64 MEMORY
FORZX81

The above illustration shows the casing for the I6K or massive 64K

r UM memory

"*oanston $41.50

Ik Dynamic Ram Chips We use the dynamic as they are much denser than
0C( :upy less space. They are also much cheaper than the equivalent product
m. The Ram is manufactured with high quality materials, and uses high
ert^ams It is supplied ready-built and only needs to be plugged into the rear of
^11 the components are fitted into holders. This massive add-on memory
3 ou fully assembled and tested is the cheapest 1 6K memoy available any-
. ,y- memory from 16384 to 32768. (Same as the Sinclair memoy .)

T6K (UNCASED) $35.95

Ex panslon $135.00

lfc rmation on the 16K also applies to the 64K Memoy Expansion, but the
n t he 64K giving nearly FOUR times the memoy. This advanced model has
ier nay. In addition, the block from 8K to 16K can be switched our to enable
r Jd-ons. The graphics ROM is to be used in this area. Position in Memoy:
e ^ ilotk From 8 1 92-16384 is switchable. 64K (UNCASEDJS 132.00

no ry Expansion $54.00

pei rtrum to 48K of user Ram, The Spectrum memoy expansion is simple to fit,
^ nside the case, and then only requires plugging in. Full fitting instructions
^ :he only tool you will need is a screwdriver and just two minutes of your
, fP quires no electronic skills. Position in memoy from 32768 to 65536 (The
-s , jpgrade to 48Kj.

jTplMse state type of machine, which Horn memory we. quantity arm place when ordering

Please send me . @ $ . .

Please send me . . . . . @ $

Please send me . . . . . @ $ . . . .

Please add on $ 9. 00 for P/P
In enclose cheque/P. O, payableto DK T ronres total
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Tel: (0799) 22036 (trade enquiries please telex 61653 attn DK)

dttronics

New colour brochure now aviiUble, tend $1.00 tor quick return

For more in/ormatjon, cirde 13 on reader service cord.

Character

Decimal

Character

Decimal

Character

Decimal Character

Decimal

blank

112

9 7

113

114

115

100

116

101

117

102

118

103

119

(

104

120

105

121

106

122

107

;

123

106

124

109

125

110

126

111

127

Symbol

blank

Decimal

128

Symbol

■

Decimal

135

■

129

136

■

130

137

■

131

138

' ■

132

■

139

133

140

134

141

■

142

Figure 3* The decimal for each alphanumeric character and the graphic
symbol for the prst set of color are shown. Seven more sets follow in different hues.

There is only one interface pro¬
blem remaining. Since the ROM
which resides at location 00 is
enabled each time the address ex¬
ceeds 32,766, some means must be
devised to keep the ROM disabled
each time the VRAM is addressed. If
a five volt level is applied to the
ROMCS trace of the backplane the
ROM’s output is tri-stated or held off
the data buss. Since there is a drop¬
ping resistor on this enable pin, no
harm results when this is done. A
2N2222 NPN transistor which is
driven by the multiplexing pulse of
the address decoder accomplishes
this nicely.

Color Modulator Operation

Sadly, the rf modulator that
comes with the T/S,ZX will not han¬
dle color signals and a new one
must be built. This task is greatly

simplified, however, by the use of a
MC1372 color modulator chip. Just
hang on a 3.579 Mhz color burst
crystal, a few capacitors, several
resistors and a .01 uf RF choke and
color comes through beautifully.

There are four color signals
generated by the 6847 VDG, The
luminance signal contains all of the
black and white information along
with sync and blanking signals.
The three other lines contain the
color information. A video clock
signal is generated by the color
crystal and its associated
capacitors. These components
generate the pulses that scan the
VRAM and output the stream of
video information to the modulator.
The RF frequency is generated by

the inductance circuit across the rf
tank pins 13 and 14. A capacitor
value of 56pf along with a .01 uf
choke should transmit to channel 4.
Some experimenting may be
necessary here depending on your
wiring techniques and other
variables including how well your
television’s fine tuning operates.
This entire modulator circuit
should be enclosed within a metal
shield to reduce stray RF and keep it
from entering other televisions
around the neighborhood.
Without the shield, my color signal
could be read all the way from the
basement to the bedroom television
upstairs. My wife and the Fee
frown on this sort of thing.

Video Signal Multiplexing

Although it is possible to use two
modulators for the two video
signals, the multiplexing of the raw
video signal is easiest. Therefore,
both signals can use the same
modulator. Three gates of a 4066
switch are used to route the signals
to the color modulator. The control
for this is, again, the select pulse of
the 74LS138. This time, however,
we are using the next pin up on the
chip which gives a select when the
addresses 38912 through 39935 are
called. I used 38990 since this
number is easier to remember. But
any number in this range will
switch the screen. One section of

Video

Figure 4, Block diagram showing address and data paths.

TIMEX SINCLAIR USER

the 74LS02 nor gate is used to com¬
bine MWR in order to avoid screen
switching when the ROM is using
the high address line to update the
television frame counter.

Wire- Wrapping The Colorboard

I strongly suggest that an Archer
44-pin wire wrap board be used to
mount the components. These are
readily available along with the
matching edge connectors. IVe yet
to find a connector and wire-wrap
board locally with pin spacing of
the computer's backplane. The 46

Figure 5. Shows connection of signal
wire from T/S,ZX, A toggle switch could
he added that reconnects the wire to the
original modulator.

pin wire-wrap socket that I mail
ordered for this project cost a small
fortune.

Since much of the wiring in
Figure 2 is “ daisy-chain, " I used the
Just Wraptm method. This tech¬
nique is very fast since it eliminates
all of the required stripping. Just
remember to wrap at least five
turns on each post and a good con¬
nection is assured every time. Its
only disadvantage is that you run

out of space on the post if you have
to wrap more than three connec¬
tions to one point I switch to
regular wire wrap when I start run¬
ning out of space on the wire wrap
pin.

The best method of assuring that
all lines have been connected is by
making a photocopy of the
schematic and checking off each
completed connection with a red
pen. Because there are so many
lines and connections, this method
can later save hours of circuit trac¬
ing. Connections can be missed if
some means of checking is not
used.

Unless you have wire-wrapped at
least 100 projects I recommend that
each chip be labeled with a small
strip of paper glued between the
pins. Pin 1 of each chip should be
clearly marked. This is a tedious
procedure, but can save hours of
rewiring a section that is wired
backward. I speak from experience.
Every other pin on the 40-pin chip
should be numbered to reduce pin
counting and probable errors.

Stacking The ram Chips

Even though two 2114 ram chips
could be used, and probably should
be, I elected to use 2102s since I
had a few gathering dust. The
disadvantage, of course, is that
eight chips take up a lot of board
space, use up a lot of wire wrap and
cost a bundle in wire wrap sockets.
Since all of the pins of the 2102s are
wired in common except two on
each chip, I've found it easier and
cheaper to stack these chips in two
groups of four each. The pins in
common are soldered to each other
and the data in and data out pins
are bent carefully out at right
angles and the wire wrap is
soldered directly to these. This
method only takes two sockets and
one fourth of the space and wire.
Just remember to use a good quali¬
ty, low-watt soldering iron when
soldering the pins.

All of the discrete components
(resistors, and so on) are inserted
into two 14 pin wire-wrap sockets.

Screen Mate

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Joystick adds versatility to your ZX0 1 or TSiOOO

* Play Action Games

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the TV Screen-

* Features a 'Piggyback
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* Draw and Doodle

* ideal tor Educational
Programs

* Independent ol
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$39.95 includes

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64K RAM

FOR TIMEX SINCLAIR

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TIMEX SINCLAIR USER

All resistors should be l/8th watt.
Figure 6 shows the suggested com¬
ponent layout but placement is not
critical except in the modulator cir¬
cuit. Remember to keep the runs as
short as possible for this section.

Scramble type wiring seems to
work best because it seems to
reduce crosstalk. At these high fre¬
quencies it may be necessary to add
several .luf decoupling capacitors
across the power traces at various
locations. 1 haven’t found this
necessary, however.

ing the second screen. This could
get to be quite a headache if you
called the two screens very often.
However, frequent switching bet¬
ween screens will usually be done
only when a program is being
checked for proper operation or
bugs. Once a color program is run¬
ning, there is little if any need to
switch between screens. It is quite
possible using software, to call a
copy of the computer program onto
the color screen for viewing. This is
the technique Fm exploring now.

Fine Tuning

Due to the two entirely different
loads and sync frequencies of the
video signals, it may be necessary
to fine tune the television after call-

Construction of the Backplane
Adaptor and Motherboard

The colorboard will operate just
fine with only the original IK or 2K
RAM. Most T/S,ZX owners have or

will eventually buy the 16K RAM
module. You may want to use the
colorboard and the RAM pack at the
same time; if so, you’ll need a
backplane adapter. Since you pro¬
bably will want to build other pro¬
ject boards, you may just as well

Figure 7. Printed circuit board for buss
extension. The use of 1/8 inch adhesive
layout tape simpli/Ies the etching pro¬
cess.

add a motherboard now. It doesn’t
have to be fancy as long as it works.

One might be constructed using a
small piece of double sided pc
board, three 44-pin connectors, a
46-pin wire-wrap connector and
two aluminum angles. The angles
can’t be high if the connector is to
match the backplane. The PC board
is etched on both sides as in Figure
7. 1 used used 1/8-inch striping tape
as the etch resist and put the board
into a pan of ferric chloride etchant
for 20 minutes. The traces came out
surprisingly well.

A pin-out diagram of the T/S,ZX
backplane is shown as a part of
Figure 1, and corresponds to the
control lines leaving the color-
board.

A Word of Caution

CMOS chips (and some low-power
ttl) are very susceptible to damage
from static electricity. Take every
precaution to eliminate static build¬
up on yourself. Avoid wearing syn¬
thetic clothes and sweaters while
working.

Never work around carpet and
plastic sheets. Always keep the
chips in their protective foam until
you are ready to insert them into
the sockets. Always double-check
the circuit before inserting the
chips. Check the power to each
socket with an ohmmeter first. If a
chip is inserted into the socket up¬
side down they are usually ruined if
power is applied. I’ve operated the
board for two months and no pro¬

vider Gul

fwo

wire-

wrap

14-pin

sockets

RF CHOKE

XTAL

R5-6

IC2

0 © 0

T7-

v7“

IC9

IC 20

IC 21

"CT

ic i

-TJ-

10-13

14-17

ice

"TT"

fC 19

IC 7

"T7-

1C 18

-OT¬

IC 6

"O’

IC 5

v-H

IC 3

IC 4

I ★ power

I despik/ng
.05 uf
ceramics

Figure 8. Diagram showing placement of components. The layout is not critical.
Keep the components for the modulator as close as possible to lessen wire runs
and for proper shielding.

TIMEX SINCLAIR USER

blems have been noted with either
the colorboard or the computer but
nothing can be guaranteed in this
business.

Operation and Troubleshooting

With the RAM pack, colorboard
and motherboard disconnected
from the computer, verify that the
T/S,ZX is operating properly and
transmitting to channel 3. Switch
the power off and attach the
motherboard only. Verify that the
T/S,ZX is operating properly. If not,
you probably have a short in the
wiring or traces of the extension
board. With power off, insert the
colorboard firmly into its connec¬
tor. Turn on power and you should
see the K cursor come up on the
screen. If not, remove power im¬
mediately, The power could be
shorted either by a wiring error or
an upside-down chip. Never leave
the power on for more than five
seconds unless the cursor is there*
If all is well, tell the T/S,ZX to print
something. It if does, at least the
colorboard is holding its signals off
the buss. Try a short program to
make sure all operations are fine,
You may note a slight herringbone
effect on the screen because of the
RF of the other modulator. This is
no problem. If there is a problem,
touch each chip on the colorboard.
An excessively hot chip indicates a
short. Trace your circuit and try
again. If everything operates but

Program

Comments

5 POKE 38990,1

switch screens

10 LET Y * 37888

star; of color screen

20 LET X * 0

decimal value of first
character

30 IF INKEYS - ** w

wart

THEN GOTO 30

40 IF X * 255 THEN

stop if all values entered

GOTO 70

50 POKE Y.X

place character on

screen

55 LET Y = Y+l

increment address

60 LET X = X + 1

increment character

value

65 GOTO 40

do another character

70 STOP

Figure a* Test Program for the T/S*ZX
colorboard prints complete set of char¬
acters and graphic symbols.

there are dark bars that move slow¬
ly up the screen, then the power
supply is being loaded down and
the filters are letting ripple through.
Don't operate with this condition.
It will cause glitches and shorten
the life of your system. I have the
650 ma supply and no ripple is
noted. It seems to handle the load
just fine. I understand that some of
the earlier systems came with
smaller supplies. You may want to
check your supply before starting
construction. If you still get no cur¬
sor but occasionally a stable fouled
up video, the multiplexers are pro¬
bably letting data or addresses onto
the buss either because of a wiring
error in the control lines or a bad

When using CMOS
chips, guard against
static electricity

chip. If the T/S,ZX operates right,
you are now ready to check out the
colorboard.

Plug the T/S,ZX into the new
modulator and switch to channel
11, With the colorboard and
motherboard plugged into the
backplane, turn on power. You
should see the screen change
radically when this is done. Yoi.
may get a weird pattern which
means that the RF is reaching the
television but your tuning is not
correct. You will have to fine-tune
until a clear picture is obtained. On
my first try, I even had to switch
over to channel 8 before a good pic¬
ture was obtained, i had used a dif¬
ferent value choke which I felt
would work.

Once you get a clear picture, you
should see a complete screen of
characters in a random mosaic and
in various colors if you’re con¬
nected to a color set. The use of a
black and white set is fine for
testing, however. A set that has a
wide range of fine tuning makes
finding the picture much easier. It
could happen that several variables
and a small width of fine tuning
work to your advantage. If the co-

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For more in/ormo(ioii, circle 17 on reader service card.

TS1000/ZX81

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Details:

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Cheques/Money Order payable to
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For more information, circle 18 on reader service card.

TIMEX 1000 ZX81

CHRISTMAS SPECIAL

H2K Ram Expansion '60 00 t ‘ S + 2 50P&H

16K Ram Expansion ‘42.95 US +2 50P&H

High Resolution Gtaphirs Cartridge
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sor, screen copy to print 1 14 pbt modes

STRATEGY GAMES j 16K required)

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For more jn/ormoliem. cirde 19 on reader service card,

TIMEX SINCLAIR USER

Figure 9* Output of screen showing a/1 alpha and graphic characters after running
the test program.

lorboard and the regular video are
close to the edge of the channel, it is
simpler to tune each of the two
channels separately and simply
switch channels each time rather
than fine-tune. Of course, the op¬
timum would be the exact setting
for both screens. Maybe one of you
will know how to accomplish this
little feat

Checking Out the Colorboard

Figure 8 is a small basic program
that prints all the graphic symbols
and the complete alphanumeric
character set on the colorboard
screen. This is the test program to
assure proper operation of the co¬
lorboard. Enter this little program
and hit run. Fine tune in the color-
board screen and touch any key*
The colorboard screen should slow¬
ly fill with the full character set
twice. If data is being entered but
not as shown in Figure 9, either
your 2N2222 is not holding the ROM
off the buss or one or more of the
4066 chips is not operating proper¬
ly. Check the wiring and, if
necessary, switch the 4066s around
to see if it makes a difference* If the
characters entered are consistently

wrong, such as As showing up as
Ts, then one of the data lines is pro¬
bably wired wrong or shorted. If
only one character is being placed
across the screen, you either left
out something in the program or
the data switches are not opening*
If you don’t get the mosaic but
rather just one character, the ad¬
dress multiplexers are not
operating and the VDG is reading
just one location* The only known
cure for most of these occurrences
is wire tracing.

The above is not meant to
discourage you but to help in case
of trouble. My board worked the
first time * * . well, at least I got a
mosaic. Two weeks later I got pro¬
per operation. So don’t feel too bad
if you have to troubleshoot a little.

Summary

I realize that many of you already
know some of the procedures and
techniques covered above. I’ve in¬
cluded a lot for the beginner. This
project is simple enough for one
who is just starting to build from
scratch, but some knowledge of
electronics is a must* Even if you
decide not to construct the board, I

feel there is a great deal of informa¬
tion here which can be used with
other projects* I'll be glad to try to
answer any questions you might
have, again just for the price of a
stamped envelope* I realize that
there is nothing invented that can’t
be improved, and would appreciate
knowing of any improvements you
make or bugs you find* 0/0

References

ZBO Microprocessor

Programming and interfacing

by f.C. Nichols, E.A* Nichols and P,R. Rony

TV Typewriter Cookbook
by Don Lancaster

Computer Data Hamming Circuits
by Alfred Corbin

TTL Databook
National Semiconductor

CMOS Databook
National Semiconductor

Parts List

Prices , supplied by a large electronics
firm in Nashvilfe, follow each item

(parentheses).

1C 1

MC6847 Video Display
Generator (12.25)

1C 2

MC1327 Color Video Modulator
(6.95)

1C 3,4,21 4066 cmos Quad Bilateral

Switch (1.17)

1C 5

74LS138 3-8 Decoder/
Demultiplexer (.55)

1C 6,7,8

74LS157 Quad 2 input Data
Selector (1.95)

1C 9

74LS02 Quad 2-input nor gate
(.25)

1C 10*17

2102 IK Static RAM (8.80)

1C 18,19

4050 CMoanon Inverting Buffers
(-70)

1C 20

74LS73 Dual J/K Flip Flop (.39)

680 ohm (.05)

5.6K ohm (.05)

750 ohin (.05)

R4,5,6

240 ohm (.05)

75 ohm (.05)

50pf (.15)

10 to 35 pf (select for best
picture) (.15)

,1 uf (.15)

56 pf (.15)

.01 uf (.15)

2N2222 npn switching

Transistor (.50)

RF1

RF Choke lOOuf + or - 10
(1.50)

All resistors 1/Sth watt
All capacitors ceramic wafer

Total cost of colorboard is $62.05.

TIMEX SINCLAIR USER

NOW ATS1000/ZX81

PUSH-BUTTON

KEYBOARD
FOR UNDER $2000

At last there’s a really cheap but
efficient way of ironing out theTS1000/ZX8rs
only real bug: its keyboard. The Filesixty
Buttonset offers

■ A full -travel calculator-type moving
keyboard for only $19.50.

■ Installed in seconds. The peel off
adhesive backing means you just register into
position and press.

■ No messy labels, dismantling or
soldering.

■ 3 groups of colour keys to pick out
shift, numerals and newline.

■ Precision moulded in ABS to match
your TS1000/ZX81, with contrasting legends
for maximum legibility

Orders to Filesixty Ltd.,

37 Fruehauf St., Buffalo, N.Y. 14226

I Make sure i he original keyboard is clean
and check that aft the keys function.

3, So aW you do remove the
protective backing

For more informal ton, circle 20 on reader service card.

Clearing system bugs

John Gilbert completes his five-part series on how to write
your own programs in basic by showing
how to find and correct errors

IN THE FINAL article of the
series, I want to take you back
to show you how a program is
constructed in a series of numbered
steps. To begin, however, I want to
discuss errors which can occur in
programs, commonly called bugs,
and how to rid yourself of them.

Much has been written about
bugs. The term is derived from the
early days of computing when only
large mainframe computers ex¬
isted, They had to be, and still are,
kept in specially protected areas
where dust or insects could not
enter the machinery. If computers
were not kept clean and serviced
they could often crash and data and
programs could be lost.

Most of the bugs encountered by
programmers occur because pro¬
gram structure is incorrect. The
statements causing the crashes are
usually the for . . . then and goto
lines.

When a program crashes, look at
the report code shown on the bot¬
tom of the screen and find the line
number where the computer ceased
the RUN. If you have been following
the series you should know that a
goto effect should be limited to one
routine. If an error occurs at a cer¬
tain line you have to look at that
routine.

On some computers, the system
offers a command which prints out
the line number to which the com¬
puter goes during operation. It is
called the TRace ON (TRON) routine.
It can be simulated if you wish to
add an extra instruction to each of
the troublesome lines. That instruc¬
tion will make the computer print
out each line number as it is ex¬
ecuted.

It is not important that you know
how it works but for those who are
interested the PPG system variable is
FEEKed and the current line number
returned from the two addresses
accessed by the statement. The in¬
struction to be appended to pro¬
gram lines is: PRINT PEEK
16391 + 256* PEEK (16392).

That instruction can be put
anywhere any number of times. It
is best to append it to the end of
lines.

It is also possible to chart the
course of for . , . next loops. It is
done by printing the variable used
in the loop. The print statement
should be put at the end of the FOR
. . . statement and not at the end of
the NEXT statement. If you do the
latter the count printed will be in¬
correct. The techniques are il¬
lustrated in Listing 1 — for GOTOs
and Listing 2 for FOR . . . NEXT.

The two techniques can be incor¬
porated together in a program and,
with the error message you get

when the program crashes you
should be able to locate and correct
the error.

When talking about these tech¬
niques and correcting errors, I
must stress again that they will be
of help only if you have used the
structuring techniques explained
throughout this series.

I have detailed the pathway to
structured programming, as ex¬
plained in these articles, as a series
of structured steps:

First: Decide what type of pro¬
gram you want and what you want
it to do. It is best to write it as a
series of statements in plain
English.

Second: Decide how you are to
handle the task and whether it can
be done with your machine and
with the level of experience you
have.

Third: Break the task into a series
of headings and sub-headings. For
example, most programs need
some form of instructive display —

Listing X

10 PRINT PEEK 16391 *256
wPEEK 16392

20 Pa I NT PEEK 1639 i + 2S 6* PEEK
16392

30 GOTO 1C

Listing 2

10 rOF; K=-i TD lu
2G PRINT K
30 PRINT
•TG NEXT K

The term ‘bugs’ is derived from the early days of
computing, when large mainframe computers were
_ protected from dust and insects

an entry procedure, a calculation
procedure and an output pro¬
cedure. They must be tailored to
meet your needs.

Fourth: Draw a flowchart. That

is that the program must be design¬
ed for ease of use, so that it can be
used by someone who knows

nothing about computers.

If you have taken my advice, or
even modified it using your own
techniques, you are on the way to
being an efficient programmer. You
will find that you can do more and
programming will become less diffi¬
cult and more rewarding, 0/0

should take a long time in many
cases. It is a good idea to draw
several charts, expanding the most
important boxes in the main one. In
that way you will know the con¬
cepts of the program before you
begin coding. If flowcharting does
nothing else it will concentrate
your mind on what you want to do.

I have a word of warning to peo¬
ple who have taken flowcharting to
their hearts. The technique is a
means to an end and is not an end
in itself. If you think a certain
number of charts is necessary,
draw them, but do not draw charts
for the sake of doing so because you
will often be confused as a result.

Fifth: Coding the program. The
code, in this case using the Sinclair
BASIC language, should be laid out
in separate modules. The control
module should be put at the top, as
it is the part of the program which
will be used most. Each module
should be complete and GOTO
statements should be local to a
module if possible.

Sixth: In long programs, bugs or
errors, are liable to occur frequent¬
ly. Bugs occur usually in the data
entry parts of the program and in
the flow structure. Flowcharting
and structured programming will
not dispose of all bugs but it will
eliminate a few.

If you have followed the series
you should be able to write
reasonably complicated programs.
As I have stressed, there are two
factors which are important, more
so than some of the others, which
are necessary to make program¬
ming easier and more enjoyable.

The first is structure. If your pro¬
gram is well-structured, it will con¬
tain fewer bugs and will, in most
cases, run faster. The second point

TIMEX SINCLAIR USER

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For Your
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KD-81 FEATURES

• Full size keyboard with 41 keys

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Dimensions are 1Z.13'* 1134%
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|1GK RAM MODULE (MX 16KP) 49.95
IhK RAM MODULE (MX-64KP) 119.00

• Suit in output connector for piggyback

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For more information, circle 12 on reader service card.

HAVE YOU EVER had a
dull, hard to remember
telephone number? David
Wahl's Dial-a-word program will
help you discover fun and excite¬
ment concealed in telephone
numbers.

Just enter the seven digit
telephone number, with
hyphenated prefix and the letters
corresponding to the number will

scroll up the screen. To pause or
change numbers, touch any key as
a line is completed.

Four and five letter word/number
combinations are more likely than a
full 7 letter word. People with 0’s
and l’s in their number should
look for combinations
like "NUMBER-1”,
“ROUTE-13”, 1-WAY”.

and “FAST-Operator".
(2K Timex/Sinclair 1000)

1 REM

2 REM _

10 LET A$="flBCDEFGHIJKLMN0PR5T

UUUIXY"

20 CLS

30 PRINT RT 10,6.; "ENTER PHONE
NUMBER”; TAB llj"E.G. 234.-5*7*"

40 INPUT

iF i_cN B$=3 THEN GOTO SO
PRINT PT ““

GOTO 40

§0
y 0

100
1 10

3 .= 6 ;

SCROLL
FOR R = I
FOR B = i
IF CODE

TO 3
TO 8

B$ CB) <30 OR CODE B$
(B ) >37 THEN PRINT ;

I20 IF CODE B* CBJ <30 OR CODE Bt
(B) >37 THEN GOTO I4-S
ISO PRINT RtCCMRL B$ CB) -I) *3 -IN
T CRND*3) ) ;

140 NEXT B

PRINT M " ,

NEXT R

IF INKEY $ = 11 THEN GOTO 80
PRINT RT 0,0;

150

100

R MOTHER HUH

190 INPUT C$

200 IF C $ 1 1 j = ”Y "
210 GOTO S0

THEN GOTO 20

TIMEX SINCLAIR USER

THE program is really a
subroutine. It will deal a
deck of 52 cards at random
without repeating a card.

The first part of the program
(lines 1000 to 1080) loads the names
of the 13 different cards into a
string variable C$. This could have
been done by 13 LET statements
such as LET C$(i) * "ACE" and LET
C$(2) * "DEUCE" and so on, but this
little routine is my substitute for a
read/data statement in Sinclair
BASIC. Put ail your data in A$ with
no spaces between items, and put
the number of characters in each
item as a two-digit number in B$,
Thus, the first two-digit number in
B$ is 03, signalling the fact that the
first data item in A$ is three letters
long. By setting up data in these
strings you can consecutively load
data into C$. This mimics a
read /data statement.

The second part of the program is
a random number generator. This
routine will generate any number
of random integers without
repeating an integer. Those who
have used the rnd function know
how frustrating it is when the
machine randomly comes up with
the same number three times in a

row. This "■ ^HffTTTT
program allows no
repeats. By changing the number
52 in lines 1110, 1120 and 1130 to
any number you wish, the program
will count up to that number in ran¬
dom order. The higher the number,
the longer the program will take, I
must warn you that the machine is
slow at this, even in fast mode.

Lines 1290 to 1350 are a simple
print loop assigning suits to the
cards and printing them on the
screen. You’ll get a 5 error when
the screen fills. If you hit cont,
you'll get more cards. The print
loop is just to show you that the
program works. It’s up to you to
think up applications for the com¬
puterized dealer. For instance, you
could delete lines 1290 and 1350
and put in a new line 1290 which
brings you into your main program.
Then you could use a GOSUB i3qo to
deal a card. Remember to advance
the value of X after each card is
dealt and remember to put in a
RETURN command at 1350.

May the cards be with you.

Submitted by Frank Terranella of
Sloatsburg, N.Y.

(T/S 1000, 1500,2X81 16K),

n m.‘

1000

1001

1005

.*51
ING “
1010
30405

1020

103O
1035
1040
1350
- TO
1050
1 0 '70
10 30
1 100
1110
1120
1130
.140
115C
1200
.210
_22D
12 30
1240
1250
1259
1290
1100

13 30

l N ’ B £

:aP£ f.

A 5T

_5” -i= *CEDEwCET«pce*GuP*I

?E E*iEIGHTNI*i£TEN_‘,9Cf £U££n*
.5* :$: 03050*04.00.0 30505040

.5 N*0

: :h :s 1: =

*gp 5^1 TO _£N £5 2

.5" : 5 3 =ae u+i if

P + 1 = -f N

_=T tsisUftL £s 4 TO A + l + N

4ET

nE*t e

4£H PflMDOM = 3 If" INE
*0P *=1 TO 52

.5” - ■ ■ slN

1 THEN GOTO
5T *>.-1

I- 4 ■ a The*- GCT- 12 2 0

1.130
-H~ = ■' - 1

:* =0 then -.e*~ ■

_ ■ =52 then got: 1210

- =1 TO 52

IF H r. : *13 Cf.P

3= 5PADE5

IF a ■ =14 and a ■ =25 TH

3 2 A MON

3 I ■ A ■ - 1 3

A ■ *2" AND a

- ' ■ _■§ A . 11 - 2 c

3* A ■ =40 AND A

I- -T C £ A • - 2 9

:: m

TIMEX SINCLAIR USER

THIS is a fun and humorous
program. You input a list of
nouns, verbs and adjectives,
and the computer creates a poem.
The poetry is of somewhat lesser
quality than that produced by Joyce
Kilmer, but somewhat better than
the stuff members of the Beat
Generation heard in coffee houses.
As a matter of fact, it falls within
that genre.

The program is user friendly, and

can be shortened considerably on
that account. The nature of the
verses(?) produced can be changed
by altering lines 730, 740, 750 and
760, Alternative words can be
substituted in lines 590 to 635 and
645 to 690. The program is fun to
play with, and can produce ex¬
tremely interesting results.
Submitted by A. Peter Hollis of
Wilson, N.C. (T/Sl000,1500,ZX81
16K),

0 PRINT AT - li ~hERE,

T C ' 'I -H .'OUR FRIEND COMPU¬
TER , WE FRIENDLY COMPUTERS a^E
REALLY QUITE TflLENTED AND I REA
TIUE. I ..05^ KNOW • OU FIND Tha-
HARD TO EEL IE YE BUT I CAN PRO1.
E IT, HOWUOULD YOU i_!KE T0 HELP
ME WRITE A ROE“ ^ WANT TO GIVE IT
A TRY?"

£5 PRINT AT £0.0 ENT EC
VE5 OR • N — -NO-"

30 INPUT 01

35 IF 0*= N" THEN G0SUB 340

4.0 IF Q S = N" THEN PRINT hT - O

' ON DON' T Be SUCH A SILL rr. INS
, OF COURSE YOU WANT TO HELP ME
WRITE A POEM p BESIDES IF nn
D0N0T I SHAll ZAP YOU * I SHALL
HAUE All YOUR CREDIT CARDS U0
ID -EC . WE FRIENDL, COMPUTERS PRE
NOT WITHOUT WORLDLY POWER E;
EN IF UE ARE EXTREMELY SENSITIVE

AS IF Qi= n then GOTO SS
50 IF 0$= THEN G05UB SAC

55 IF 0$- v- then PRINT AT - 0

"OH I AM SO GLAD, I JUST KNOW
THAT IF YOU HAD SAID ■“'NO" I
SHOULD HAVE DONE SOMETHING T
ER- PIBLE PERHAPS I SHOULD hAVE
CAUSED YOUR PHONE NUMBER TO
BE THE SAME AS THAT QF AN AlL-N
IGHTBOOKlEi WE Fp lENDL r COMPvTgp
S CAN SE SO UENDICTIJEV
60 IF Os "v • THEN GOTO 30
65 PRINT AT £1.0 PRESS ENTE
" TO CONTINUE,

70 INPUT =*

75 REH ********* /NOUNS****** **
50 G0SU6 340

65 PRINT AT 5 0 'SO, WE BEGIN,'
90 PRINT

95 PRINT ENTER 5 RELATED
g OF S LET- TEAS CP LESS , (HI*

NONSENSE WORDS APE never fore
IDDEN, ) "

100 G05UB 370
105 LET CT *1
110 l£T A = 1
115 DIM HSiS.g)

130 FOR Y*U TO
125 GOSUB 910
130 INPUT ABC R.

135 IF R$(Ai A ■

" THEN GOTO 130
140 PRINT at y ■ 13: AS A
14-5 GO SUB 9 £5
150 INPUT Os

155 ip OS = - N ' then GOTO 125
160 IF Of t:Y ' THEN GOT: 150
155 LET CT=CT*i
170 LET A *A + 1
175 NEXT y

130 PEM +****5 ADJECTIVES*****
155 G05UB 340

OR As . A = PNC

190 F PI
ELATED _

OP LESS,

195 GOSUB S70
200 lET CT=1
205 LET Ssl
210 DIM Bi i 5 6 i

NOW ENTER S P

_ OF 6 letters

BE DRAMATIC,

BRIGHT^ BRIG FIRE “ _ '-1 F .

i H Z N L? R !1LN Hi" RR 2 U Z ■.

Ho ~ h. 21 -Z1 H — _1 i-Z Sj H U W '“■ u V z ~

THE 5UEET EftftT“ GR0U5 DYE- .
Sl-JEET , 5wE£! EftRTH FlhMEE-

! M ^ tSJ N Z ■ * : Hir Z L- 0 W -2

H N L N Z W H - Z H' l? rr 0 U Z ■_ Y ■ Z T

THE NEW FIRE ft ft IN 5 Evt- .

■" Kt Tt*’ : ^ K£ w*H NhTzR OR L: -■ Z

'=LIPFT ?aDTw Pi ft! E-s

T Z HH“. ' U H ~ IHL

o J J Z V

'HEN GOO

) “PT Q:j

'i1 U K i L.

jN;

hBuLH

UNEN 5NEET zhwTh BLOUz
■Z NzU ZHH : H -"LiEi J U ’Y u u z
0 *■ B R I G H 1 W H ; z h: FzftMEz — _

THz PURPLE LHhlE FLIES IN,
F£~ rftT NHftLE DROPS
W H z N 1 j P z H z* ' !’’ y “HlE J U H P z
r h£_P jwFlE 0 u ft I _ i_ E h P 3 ft S 0 UT
OP_RrURRLE MOOSE zEftPS PGhIN.
puhPlE PURPLz WHftLE DROPS
THEN PURPLE CftMEL LEftP -

Hi frt chmel flies pgr in

ft 5 G 0 0 E' ■■" M 0 0 5 E U H P S ft B 0 ,

r: ; Hr- up:

U ftp IftL

LULL

— — - — ■— vJ " ■ — P : v j_ «_ Z:

_ Z v Z N L ■ H H K :.-J H7ZK . J ft I T S
ft Dftfth EftRTH DIES DfiRKL
ft N S u u L D t i H z y ft IT z Mz uz — «
DftRK DftRK NIGHT US ITS
UHft I D EhD G L 0 OM y ft jt 5
SO SLACK NIGHT CRIES NzUER
5 0 S L H C K N l G Hi o Q 2 E S S = ft ft K
DkzhD , DREftiD zftRTH DIES
i H z u l L; N i L H r 0 OZE z ,

THE DftRK U PTE ft LIES hUFUl
H 0 W D KiiHi LL Q 0 M D I E 3 C: E ft D L

!* H

' G L u E v

‘HE Ffty

C ft MEL LEAPS
GOOSE JUMPS
iSE RUNS IN ,

jHFL JUMPS IN,
:Y UHftLE RUNS
CAMEL JUMPS

Fup LZri N U JJH J-L L E ft P Z i sN :
ft PURPLE UHftLE f^jes UHOOPS ,
GOOEY GOOzY DA MEL RUNS
EUER FfiT OhMEl FLIES,

FOR LEAN MOOSE DROPS WHOOPS
H Li Lr U 0 U E U U H I L LEhP Z' 0 L* s

£15 FOR f =li TO If
££0 505UB 910
££5 INPUT Bi-B-

230 IF f^; = ; h OP Si f = ci*;:

THEN SOTO 225
235 PRINT RT ■ 13;S*'.E

S“0 SOSuB 925

245 INPUT Os

£69 IF 01= N THEN GOTO 220
255 IF OS : Y ^HEN GOTO 2 4-i

sis if oi= u- then PRirr

0 PlES55 RE-ENTER

515 IF 0*- N The** GOTO 435
520 IF OS THEN GOTO 505

525 PEN -*****SET PERD'.- *-**±*«
530 305 UE 540
535 fqr 5 = 1 TO: f
S4.0 FOR F = 1 TO

260

_ET CT =CT * l

545

PR Jf,

>T A~ 10 " o-

265

wet e*B+i

, 270

NEXT ¥

550

- . p- j -

! £75

REH *****-#*c -:ERB 5 - *

555

FOP"

G = 1 TO 5

■!' 230

905lE -340

560

PRINT AT 10 0; OKA’ , GE“ PE

' 255

PRINT AT “ o

, NOW ENTER 5 P

ADY .

HERE IT COHES.

ELRTEO 3Maai of 5

LETTERS

OR lE

565

NEXT G

155.

: HINT STA v

MOSTLY

IN the

570

NEXT E

S SAME TENSE. )"

^7^

REM

^ARTICLES CON j U NOT 1 0 N 5 *

290

G03UE 370

530

GO SUE 340

: £95

w£T CT = 1

F£F

DIM

P| 10 4

300

LET 0=1

590

— ET

F S 1 1 1 = A

: *.Q*

LIN IS 5 6:

595

^£T

- S ■ 2 ; = the

i 310

FOR =11 TO

600

_ET

F * : 3 •: = THA-

i 01?

GGSUB 910

605

_ET

” 5 ; 4 ! = THEN

1 3£0

INPUT C * m: :

610

LET

F £ : f : = 4 MEN

1 325

IF C 5 : C ; P

or c s :

= PND

615

_ET

- s 6 : = WHAT

THEN GOTO 320

620

^£T

Ffi:?:ts-:WH

1 530

PRINT AT . 13 , 0 5 C :

625

^ET

-5 =1 = HQ

I 335

G0SU3 925

630

LET

F* : $ ; * E -;EP

340

INPUT Oi

535

-ET

= S : 10 : = EUEN

, 345

IF QS- N" Trt

EN GOTO :

640

DIM

G 1 ; 10 3

350

IF QS THEN GOTO

340

645

^ET

£ S ; 1 ) * A

35?

LET QT *CT 4 1

650

i_ET

3 S : 2 t = THE

360

_ET C=C*1

655

lET

9 S : 3 : = AN:

365

NEXT v

560

^ET

Gi ; 4 1 = BUT

370

PEN 44**4**D

AD U ERE z *

+ *. + - T *

665

lET

G S : 5 ; = OP

375

G05U3 340

5'T0

LET

G $ 1 6 ) = A 5

: a 0

PRINT AT - o

. NOW ENTER 5 S

67?

i_ET

Gf:~:= FOP

m of e e_et -

TEAS OR

LESS .

630

lET

;i s?= so

’HINT THIS IS A

GOOD PLACE FO

635

LET

G $ 1 9 '| = :

R RHYMES. i

690

lET

Gs : 10 : = * HOW

335

G03UB 370

695

REM

■*4 4*P0EM flCN£ftA”3P44-

390

l£T CT=1

T00

PRINT AT i 0.E s

395

let p *1

-*05

FOP

X =0 TO LEN ElL

400

DIM Dt’5 6

710

PRINT AT 5 X "

405

FOP . =11 to

715

NEXT ^

410

G03UB 910

-20

FQR

=6 TO 17 STEP 4

415 INPUT os «r ■
420 JF D»»D‘

0P D$ L

5ND

72 =

730

GO -SUE 940
PRINT qr ,

= i 5

- THEN GOTO 415

I - 5 $ ; 6 TO

I : a a 1. A

425 PRINT at .■ 13; Da l

Hi . C % I C TC

J) .; :: . ”

430 GO SUB 925

73f GOSUE 940

435 INPUT Of

-40 PRINT AT + 1

0 F J ; =

440 IF 0 $ = " N : ' THEN GOTO 410

L ) = B* ;.E: TO

1 1 a a I a

4 45 IF Oi 'V THEN GOTO 435

Hi C S : C TC

j) ; Z

450 let ct=*:t+i

^45 G05UE 940

455 LET DsD+1

^■50 PRINT AT ,■ *2

.0 Gi 1 G

M3 i

460 NEXT v

E i 1 E TC I ’

AS A

465 PEN TITLE . .

C * C C TO

Di D

r ) ,

4^0 GOSuE 340

4-? PRINT AT " Q -iAUE CL* ThQU

^55 GO Sup 940

GMT CF A title =qp OUR P0EM7 2 K

^60 PRINT AT <■ *3

0 Gi ' G

Ml :

INC CF like ODE tqa NIGHTENGAL

E S 1 E TQ I: •

A* 1 A

H :

E OP IT TAKES A HEAP R-lT-

C $ tC

1" ) >

in. on the or hep 7 an: ^rees

IS KIND C5 SNAPPY. NO" OF vflu

76E NEXT t

APE 50 GOO: at TITLES ~HEn -Q

770 print at 20

0 WOULC

YOL

L DECIDE,

he a printout-

ENTEP

430 PRINT AT 20.0 ENTEP ~I“_E.

E f OP N -NO ,

; NOT MOPE thaw one LINE PLEASE

-75 INPUT Ql

. ) "

455 INPUT ES

490 IF Ef= THEN GOTO 435

49^ crinT T 0 ;i
500 G0SU6 925
505 INPUT c$

-50 IF 0 $ = " N
^55 IF 0$= ■ ■
-90 IF Os
-95 print rt •

til Tm the 59 TE
*"v - v 5 5 OP

then GOTO ^9f
then go SUE 10^0
THEN GOTO
:0 . 0 RNOTHER POEM
WORDS' Enter
hr -NO.

then GGt: 530
THEN GOTO 500
0 0 want — o up 3

ENTEP 11

300 INPUT Qs
■505 IF 0$= V

510 IF OS ■ N

515 PRINT hT
E ANOTHER POEM
VES OP " :U -N
320 INPUT Q*

325 JF 0:t= v" THEN GOTO 5 0

5 30 IF O' S — N' Then GOTO IQ90

335 IF Of " N THEN GOTO 320

540 C EM *;t**Tf*ift**t - - - -

345 FOP • =4 TO 21
350 PRINT RT , 0.

355 NEXT Y
530 RETURN

365 REM + t * - ***^.»**»*

370 LET x=5

375 LET n*1

550 fqr v =11 TO If

355 PRINT AT • 10. N .

S90 LET N*N+1
595 NEXT y
900 RETURN

905 PEM -4* + ********-*-i
910 PRINT qr z? £ ENT
UMBEP ; CT

Eft wop: n

915 RETURN
920 PEM
925 PRINT RT
CORRECT “

YES OR " :,N-; J3 -N

00 IS ^HE
ENTER

SNTP .

9 30

RETURN

935

PEM

940

^ET

A = INT

pn:*5 -1

244

LET

B = INT

■RNDkS; +1

950

LET

C*INT

PHD 45 rl

955

LET

: =IwT

: AND 75 ' 4 1

960

LET

F =INT

; RND 410 - +1

965

lET

G =INT

an: *10 4 1

9'0

FQR

h*len

A* -A' TO I STEP

9-5

; s

R§ : A Hi

" 1 THEN GOTO 9

960 NEXT H
955 FOR: I=lEN
990 IF £S i.E Is
000

995 NEXT I
1000 FOR U=l£N
1005 IF C $ ! C .. v' =
015

1010 NEXT U
1015 FOP r =LEN
1020 IF DS<0;K:
030

1025 NEX
1030 FOP
103!

045
1040 NEXT l
1045 FOP M=lEN
1050 IF Oi : G m

!S ‘5 TO 1
THEN

:% c ■ tc i
then

li : tc i
then

_EN F
IF FS : F J_ :

S I. F TO 1

T>-fE'.

G ■ TO 1
THEN

STEP -1
GOTO 1

STEP - 1

GOTO 1

STEP -1
GOTO 1

STEP -1
GOT 0 1

STEP

RETURN

1055 NEXT h
1060 RETURN
1065 PEM **if***it + --
1070 PRINT RT 20 0

1075 COP.

1050 RETURN

1035 PEM *4 **-**-*,*

1090 CL3

1095 PRINT AT 9 11
1100 fop i_ = 1 TO 50
1105 NEXT L
1110 NEW

SOREHEAD.

THIS is a game that allows
you to draw a picture with
the cursor. To erase
something (move the cursor
without leaving a trail), press E,
and to draw again, press R, When
you are finished, type A, To
retrieve a picture previously loaded
onto the cassette, type Y.

Submitted by Alex R. San Miguel
of Tenafly, N,J.

(T/Sl000,1500,ZX81 16K).

1 PRINT

£ PAUSE
3 PRINT
5 MOLE THE
I FT 2 , DOUN
UP RIGHT
.RIGHT '

AT 10., 9 SI3HS VBPK
200

THE pQluOUING NUHEfP

- : :ra- : . _p _

vE^T 3, DOUN RIGHT
5 * LEFT 6 .DOUN 7, UP E

4 PRINT t\ pe E TO ERASE OR -1
DUE PI*Ei_ -ITHOUT DRAWING, T P
E R ’Q DRAW AGAIN Tv PE A TO 5T0

5 PRINT AT 21 0 " f PRESS ANY h

EY i "

6 PAUSE 40000

$ PRINT A” 21 O DO YOU UA N*
i_A5T DRAWING^

9 INPUT L S

10 IF Li- THEN GOTO 199

11 CL5

12 DIM F ? 53 • 42

13 wET X =31

14 LET v =£1

15 ^ET 5=16

16 UNPLOT ; ■

17 PLOT X . ■

INKE S= 5

INKE r 1"

INKE 1=1"

INKE • 1 c ’ 6 ”

INKE 1= 4 '

INKE 5= 4

INKE 5= 3"

INKE ■- 3"

INKEY f=

INKE 5 = 2

INKEy 1 = 2"
5=103 THEN
5*16 then
INKE 1= R"

THEN

LET

* ■ s ■ *

THEN

LET

r ~ .. -

THEN

LET

= -

THEN

LET

= -

THEN

let

THEN

LET

‘ = 3 ~

THEN

let

THEN

let

* — ■ *

THEN

LET

= *

THEN

LET

= -

THEN

LET

' ~ -

THEN

LET

X = * -

LET =

' < X Y

= t

r'Zr l A , i • =X

THEN „ET 3=16

IF INKE ■■5= E"

THEN LET 5=

IF INKE S = "A

THEN GOTO l1

GOTO 5

100

PLOT X ,

101

UNPLOT :■ .

102

GOTO 20

150

CL 5

151

PRINT DO YOU

WANT TO SAL :

152

INPUT LS

153

if l*= then

GOTO 166

154

CL -5

155

STOP

156

PRINT SET UP

RECORDER"

157

PAUSE 240

153

PRINT Start RECORDER :

159

PAUSE 120

150

SALE U I DEO GRAPH IT®

161

PRINT "DRAWING

SAUED"

162

STOP

199

ClS

200

FOR X=1 TO 63

201

FOP v =1 TQ 42

202

if f ! > ■■ =i then plot x

203

NEXT r

204

NEXT X

205

GOTO 13

TIMEX SINCLAIR USER

10 DIM A C 33 )

15 SLOW

£0 PRINT “RANDOM PATTERN’7 V{ Q
m " '

30 INPUT A$

4-0 CL 5

50 IF NOT R*=“Y“ THEN GOTO 20

S0 LET L = INT (RND*33) +1
70 LET X=INT (RND+6S53S) +1
80 RAND X
85 FAST

90 FOR d=l TO L
100 LET A ( J: = I NT (RND*10)+1
110 NEXT J

120 FOR J=i TO 660 /L
130 FOR K = 1 TO L
140 PRINT CHR$ A (K) ;

150 NEXT K
160 NEXT J

170 PRINT X; " < " ; L; " ) ”

180 STOP

200 PRINT "PATTERN NUMBER7"
210 INPUT X
£20 CLS

230 PRINT "STRING LENGTH? "
240 INPUT L
250 CLS
£60 GOTO 80

UNIVERSAL PATTERNER
is for 16K users and pro¬
duces patterns at random.
Author W.S. Hearn states that more

than two million designs can be
printed on the screen.

Each pattern has a number and
string length printed at the bottom,
so can be recalled and adjusted us¬
ing those numbers. Answer N for
No when asked if a random pattern
is required and then input the
numbers.

TIMEX SINCLAIR USER

Five-year plans,

monetarism, the green
revolution, laissez faire and
the dictatorship of the people —
you can try them all.

Kingdom gives you a rural realm
to regulate and five years in which
to increase your personal wealth
and protect your people against
flood, famine and the depredations
of the ruthless local banditry.

You are first given instructions
for the game and asked to input
your name, age and sex. Depending
on the information you supply, you
will be dubbed king, queen, prince
or princess and then asked to
decide how best to divide your
available workforce in the season
ahead. Consider the crops, or your
subjects will starve. Bear the ban*
dits in mind or your minions are
murdered. Delay on the dykes and
they will drown.

It is reasonably difficult. Our
1,000 subjects were reduced to
single figures after the first year.

Any number can play and you
have five years in which to justify

TIMEX SINCLAIR USER

your kingship and to amass as
much money as possible by the
judicious selling of surplus grain.

Good luck, your highness, and
thanks to Andrew )ohnson, who
submitted this excellent listing
(T/S1000.ZX81}.

Fl0

18
1?
20
21
22
23
2*

53
55

57
56
59

53
55

57
100
105
110
115
120
125
130
135
150
150
170

175

176
180

PRINT AT 3 ,71 "**xx*»***********"

PRINT AT 4,73"* x"

PRINT AT 5,73"* KINGDOM*"

PRINT AT 6,73"* *"

PRINT AT 7 , 7 3 " ***:» *x***x**x*x* * "

PRINT AT 10,03 " YOU HAVE. TO GOVERN A TILLAGE" 3
AT 12,0 3 "FOR A PERIOD OF FIDE YEARS , YOU" 3 AT 14, 0J
"MUST TRY TO KEEP ALIVE AS MANY-

PRINT AT 16,03 "PEOPLE AS POSSIBLE , THEY WILL DO" 3
AT 18,0 ; "ONE OF THREE JOBS," 3 AT 2Q , 0 3
"YOU MUST PROTECT THEM AGAINST,,"

PRINT AT 21,53 "TYPE ANY KEY TO GONT,"

IF INKEY5” " " THEN GOTO 9
FOR F-l 0 TO 21
PRINT AT F,0 3 ’•

NEXT F

PRINT AT 10,03 . CA)*>FLOQDS"3 AT 11,0 3

",,,(6) ^STARVATION** 3 AT 12,0 J " , , . < C ) =>THEIVES" 3
AT 14,03 "YOU HAVE TO BE AS RICH AS POSS,"3 AT 16,0!
"AT THE END OF THE FIVE YEARS"; AT 18,03
"AND THE RICHEST WINS,"

PRINT AT 21,53 "TYPE ANY KEY TO CONT,"

IF INKEYf*"" THEN GOTO 15
FOR F= 1 0 TO 21
PRINT AT F,03 "

NEXT F _

PRINT AT 10,03 "HOW MANY PLAYERS? "3
INPUT A
PRINT A
DIM Ni < A , 1 1 )

DIM U C A )

GQSUB 7000

PRINT AT 21,5 3 "TYPE ANY KEY TO START11
IF INKEY5:= " ** THEN GOTO 35
FOR F=1 TO 22
SCROLL
NEXT F
GOSUB 8000
DIM MCA)

DIM CCA)

DIM OCA?

FOR F3*! TO A
LET M<F)*1D0Q
LET CXFMIOOI)

LET C < F ) “250 O
NEXT F

DIM P ( A )

DIM N ( A )

DIM Z ( A )

DIM X < A )

DIM UA>

FOR F-l TO A
LET Z (F ) =*0
LET X (F ) -0
LET T ( F ) =0
NEXT F
REM start
LET S=0
LET Y“0
LET S=S+1

IF S*1 THEN LET Y 5- "SPRING"
IF S=2 THEN LET Y **" SUMMER"
IF S=3 THEN LET Yf =" AUTUMN"
IF 6=4 THEN LET Y*= "WINTER"
IF S” 1 THEN LET Y==YX
IF S=4 THEN LET 3=0
FOR P=1 TO A
LEI N ( P ) = I N T ( RND* 1 0 )

LET 0(P)=CHP)+N(P)

PRINT AT 0,93 Y$3 " YEAR "3

Kingdom Revisited

Note; This program, missing
about a dozen lines, /irst ran in
Issue 3. It has now been cor-
reeled. Our thanks to the many
readers who brought the error to
out attention.

19 0 IF NS CP) <11 > = "H" AND LHP) > 18 THEN PRINT "KING "
NXPX TO 10)

193 IF NSC P) CIU = "F" AND UCP) <= 18 THEN PRINT
"PRINCESS "? N*CPX TO 10)

195 IF NSCPXll) = "H" AND U(P> O IS THEN PRINT
"PRINCE "J NSCPX TO 10)

200 IF NS (P ) C 1 1 ) = "F" AND UCP) > 18 THEN PRINT "QUEEN
NSCPX TO 10)

201 PRINT

202 PRINT NCR); " PEOPLE CAME TO THE VILLAGE,"

203 PRINT

210 PRINT TAB 93 "CASUALTIES 3 "

211 PRINT " STARVED , FLOODS , THIEVES"

212 PRINT TAB 3J X(P>3 TAB 12J Z<P)3 TAB 223 TCP)

214 PRINT "xxxit^»ixKivxiiimix»mvxixxx"

220 PRINT TAB 103 "YOU HAVE l "

240 PRINT TAB 15XULEN (STR* HCP } ) >+2>/2) ; "i"3 M(P)3
260 PRINT TAB 15-CCCLEN CSTR* G C P ) ) ) + 8 ) 72 ) 3 OCR);

" PEOPLE,"

280 PRINT TAB 15-CCCLEN (SIR* C ( P ) > X 1 5 ) 72 ) 3
"SACKS OF CORN,"

290 PRINT "xiirKxixmirxiiixxjmcomxiiuxiM

300 PRINT "LAEiOR ARRANGEMENT l "

320 PRINT " < A ) MENDING THE DYKE "3
330 INPUT A 1

335 IF INT A 1 <> Al THEN GOTO 330
340 PRINT Al

360 PRINT ** C B ) PLANTING CORN "

370 INPUT A2

375 IF INT A2 <> A2 THEN GOTO 370
380 PRINT A2

400 PRINT "CO DEFENDING THE VILLAGE 11

409 INPUT A3

410 IF INT A3 <> A3 THEN GOTO 509

411 PRINT A3

412 IF A1+A2+A3 <= QCP) THEN GOTO 420

413 PRINT AT 21,53 "TOO MANY PEOPLE"

414 FOR F= 1 TO 22

415 IF INT A3 <> A3 THEN GOTO 410

416 NEXT F

417 GOTO 180

420 IF Y4 <> "SPRING" THEN GOTO 430

422 PRINT "HOW MANY SACKS OF CORN ARE TO" 3
" BE PLANTED? "3

423 INPUT DCP)

424 PRINT DCP)

425 IF DCP) > CCP) THEN GOTO 422

426 LET CCP) CCP) -DCP J

427 IF DCP) 710 > A2 THEN LET DCP)~A2*10
430 PRINT AT 21,53 "TYPE ANY KEY TO CONT,"

440 IF IWKEYf THEN GOTO 440

TIMEX SINCLAIR USER

AT 9,14; '**
*"l AT 11

f*50 FDR F*1 TO 22
f6Q St ROIL
#165 NEXT F
[466 FAST

1-170 PRINT AT G,0i Hi
I 490 PRINT AT 8,14$ "w****s
"* ++ AT 11,11! "*

50 0 PRINT AT 10,27? "T"

5 01 LET T < P } = 0
507 LET Z(P)=ft
5(13 LET X(P)=U
50 *1 SLOW

510 IF A 1 < U(P>/2,2 THEN GOSUB 1 QuU

52 0 IP A3 CMP > /2 , 2 THEN GOSUB 20 0 C

530 IF D(P> < Q CP > *2 THEN GOSUB 30 0 0

535 LET C(P> = (C(P)/1*2) + D(P>*3
5^0 IF CCPI+DCF) < GCP)*2 THEN GOSUB 40013

550 IF C < P > + D C P > > Dtr >*2 THEN GOSUB 50 0 0

560 LET D(P>»Q(p)wi#2
565 LET 0(P)alNT CQCPJ)

575 LET CCP) =INT <C(P))

530 LET M(P)=M(P)*I »«9
583 LET N < p > ==INT (hCP) )

590 FDR F^l TO 22
600 SCROLL

610 NEXT F

611 IF MCP> <

612 IF CCP) <

613 IF OCR) <

620 NEXT P
630 IF Y < 5 THEN GOTO 115

640 PRINT AT 0 , 0 J “NOW FDR THE WINNER . . » t •

644 LET W**,IM

645 LET W“0

650 FOR F=1 TO A

660 PRINT NTCF)C TO 10); " WITH V’f MCF)?

14 J

M; AT 10,14?

"******••

0 THEN LET M<P>*Q
€ THEN LET C(F)=B
U THEN LET 0<F)=0

f 830
t TO
690
700
70S
710
ON 5
R OF
730
1000
1010
URN
1020
1030
104-0
1050
1060
1070

THEN

IF M ( r ) > U

10)

IF H <F) >U
NEXT F
POKE 16415,0
PRINT ST 20,0,

" YOU'

LET U$aN$«F)
LET U=H (F)

"CONGRSTULSTI
SRE THE UINNE

THE OS ME WITH $";W
GOTO 10000
REM DYKE

IF I NT lRND*3)+l=l THEN RET

LET K=INT <:RND*10) 45
FOR F = 3 TO K 43
FOR g=o TO 21
PRINT ST G,F;CHP$ 5
NEXT O

IF K 4 1 0 > O f P ) THEN LET K = INT
(.Q IP) /10)

1030 LET O ip) =Q (p) -K 413

1090 IF K > S THEN LET M(P)=M(F)-t

IK-3)#100)

1095 LET Z (P) = K 4 1 S
1100 LET C tP) =C l'P) -K415
1110 RETURN
2000 REM DEF

2010 IF I NT (RND*3) 4 1=1 THEN PET
URN

2020 LET K“INT (RND *10) + 5

2025 IF K*6 > Dtp) THEN LET K^INT CQ<P>/6)

2030 FOR F =27 ID 16 STEP -1

2040 PRINT AT 10 ,FJ "T 11

2050 NEXT F

2060 FOR F= J TO K

4000

4010

4020

4030

4040

4050

207O

iu, i6;

" (graphic

4)"

208O

10,16;

" (graphic

1 ) 11

2090

io,i6j

" (graphic

2)"

2100

io,i6;

11 C graphic

3)"

2110

NEXT 1

212ft

FOR F-

= 16

TO 27

2130

iq,f; "

2140 NEXT F

2150 LET Q ( P ) - Q(P)--K*6

2151 LET TCP) * K*6

2160 LET CCP) = CCP)-K*25
2170 LET HtP) = h<P)-K*15
2180 RETURN
3000 REh STAR

3C10 LET K =* ABB <D(P)-*Q(P)«2> >
3015 IF K > Q(P) THEN LET K=G(P)
3020 LET DCP) « OCP)-tlNT CK) )
3035 LET X C P ) -=K
3040 RETURN

4060
4070
4080
4090
4100
41 1 II
4120
4140
4150
4160
4170
41B0
4190
4200
4210
4220
5000
50 1C
5020
5030
5040

5050
5060
5070
5 071

5072

5073

5074

5075
5 03C
5090
5100
5110
5120
5130
5140

17000

'7010

7020

J 703C
7040
70 50
7051
7052
7060
7070
7080
7090
7100
7110
7120
7130
7140
7150
7160
7170
7180
7190

aoco

8005

aoio

8020

8030

8H40

8050

L9000

Oil]

REH BUY

LET K-INT CRNDttS
FOR P=1 TO 22
SCROLL
NEXT, F

"vini mL .°l£' CZ0U HAUEN 'T G01 t:N°UGH CORN TO FEED
PRINT y*L 'AGE-Y0U rtU£T BUY SOME , , , "

PRINT -CURRENT BUYING RATE - «;k
PRINT

PRINT "YOU HAVE S"? NCR)

PRINT "THE MOST YOU CAN HAVE ARE INT CM(P)/K)
PRINT "SACKS"

PRINT "HOW MANY DO YOU WANT TO BUY'?":

INPUT I 1 ' f

IF I > Ch< P)/K) THEN GOTO 4140
PRINT I
PRINT

PRINT "THAT WILL COST I*K

LET N(P> = H(P)-(K*I)

LET CCP) « CCP) +1

RETURN

REM SELL

FOR F“ 1 TO 22

SCROLL

NEXT F

PRINT AT 0,0; "YOU HAUL A SURPLUS OF CORN , DO YOU";
"WANT TO SELL ANY, IF SO SPECIFY THE AMOUNT * "

INPUT Af

ir AiM) = "N" THEN RETURN
LET K-V AL At

IF K <= CCP) THEN GOTO 5C80
PRINT

PRINT "YOU ONLY HAVE "? INT CCCP))J " SACKS."

IF TNKEYi THEN GOTO 5074
GOTO 50D0

LEI J =* INT < RND* 5 ) +5
PRINT K J 11 SACKS OF CORN, AT"

PRINT " A SACK, WILL MAKE "

PRINT K*d

LET MCP) = M<p)+K*J
LET CCP) = CCP) -K
RETURN

FOR F-l TO A
CLS

PRINT "PLAYER ";F
PRINT

PRINT "YOUR NAME PLEASE? "

INPUT N* < F )

PRINT Ni C F >

PRINT "YOUR AGECAPROX)^ ";

INPUT UCF)

PRINT UCF)

PRINT “ARE YOU MALE C rt ) /FEMALE C F ) ?

INPUT NtCFMIl)

PRINT Mt(F)(li)

PRINT "O *K*? "J
INPUT m
PRINT m

IF Hi®" NO" UR lit = "N" THEN GOTO 70 1C

NEXT F

RETURN

TAST

LET ill - " "

FOR \ =% TO 22

twenty
NEXT F
SLOW
RETURN

SAVE "KINGDOM"

RUN

TIMEX SINCLAIR USER

Treasure. Island

Lat- 5“ -3-f si." H

Long- SZ‘ M' II" W

miwoi't

*uif.

Treasure hunter is a

clever little game in which
a hunter, denoted by an
asterisk, has to find treasure which
is hidden at a random position on
the screen* The only assistance
given to the hunter is that he is told
when he is getting warmer.

It can be very annoying when,
whichever way you move, you
seem to be getting warmer but can¬
not find the exact location of the
treasure. When the correct spot is
found, the number of steps taken is
shown on the screen, along with
the program's idea of the optimum
number.

The first attempt by the Timex
Sinclair User’s reviewer resulted in
453 steps taken against an optimum
of five. That later improved to 84
against an optimum of 30.

The hunter is moved by using the
cursor keys but an added difficulty
is that if you go to the edge of the
screen you bounce back so that the
left and right keys and the up and
down keys become reversed.

Treasure Hunter was sent by P.
Brown.

tkpe

TREASURE

HUNTER

REM

TREASURE HUNT BY

P AND

H BROUN

LET

P = F I / P I

LET

Q=PI-PI

4-0

LET

L = INT (RND*UflL

11 15" ) 4U

RL Mi

5 J!<

C = INT (RND*URL

,l2?,J ) 4

URL

: ; i. I

LET

5=0

LET

0 P=P

LET

00=0

LET

P=P+ ( INKEY $ = " 6" )

- (INKEY

$ = “7

11 )

100

LET

0=0+ ( INKEY *="S")

- (INKEY

*= ‘5

“ 3

110

CL5

120

PRINT AT P , Q ; *' * “

130

LET

S=S+PI/PI

140

IP P

' =L RND 0=0 THEN

GOTO UR

L M2 10 11

150

LET

D =L -P

160

LET

E =0 -0

170

LET

F =L -OP

180

LET

G=C-00

190

IF RB5 D+fiBS E;RES F + RB5 5

THEN

PRINT fiT 3 , 0; "UfiRMER"

200

GOTO

! URL ”70"

210

PRINT RT L,C; " X "

220

PRINT "LOOT FOUND IN

" ; 5; "ST

EPS1*

230

PRINT "OPTIMUM".: L + C-

URL "I"

TIMEX SINCLAIR USER

— ~ WANT TO BUILD \

YOUR LITTLE

TIMEX/SINCLAIR

INTO A REAL COMPUTER?

Try our plug-together systems.

MEMORY TO
1M BYTE
HI SPEED TAPE
CHARACTER
GENERATOR
TRANSISTOR
DRIVER

RELAY DRIVER
A/D CONVERTER
FLOPPY DISC
POWER SUPPLY
CENTRONICS

SOFTWARE

KEYBOARDS

I/O PORTS

SWITCHES

CONTROLS

JOYSTICKS

HIRES

EPROM

SPEECH

RS 232

PRINTERS

Dealer Inquiries Invited.
Catalog— U S. Free, SI. 00 Outside U.S.

Screen monitor
saves eyesight

The Gorilla seems to have
done it ... an under $100
monitor for the under $100
computer. The high-
resolution, green screen,
non-glare monitor is selling
For $99.

The non-glare screen not
only makes long-term view¬
ing easier on your eyes, it
also eliminates annoying
reflections. Special
phosphors switch fast but
flow evenly to prevent
screen flicker and the

eyestrain that goes with it.
Those same phosphors stop
scrolling characters or fast
flying spaceships from ap¬
pearing smeared or streaky.

The crisp screen displays
at a video band width of 18
MHz or better a full 25 lines
of 80 characters each [2,000
characters). The sharpness
of the display enhances
graphics on the screen also.

We liked the built-in tilt
bracket. Using it, we could
angle the monitor for our
best viewing.

SlwcfiatA ^PCace

P.O. Box 2288 A * Redmond, WA 98052

For more information, circle 21 on reader service card.

R.I.S-T. Inr ANNOUNCES

SPEECH

SYNTHESIZER
SALE °>

* ACT NOW: Receive

Exclusive Phrase Finder Program "$S. VALUE FREE '
Speech Synthesis Instruction Manual '$10. VALUE FREE
ORDER NOW SALE ENDS 9/30/83

ME Aff TMI POWER

if SALE

rttf liS*nd T* *

.O’ i1 Dipt. 1* —

u_= — .

1*0.1. me
(Fomtrly

FO. Bom m. H

Brooklyn, N.Y
(2121 -

gorwit* an

HOW YOU CAN MAKE YOUR COMPUTER TALK.

Th# PARROT ftbwfy mtroduc#d by RJ.S.T.. givai tha
pgvw*f of tptech to TMH/llMMr Compute Ttw nm pm
ip uh plug- in kpMch modulo it capabit of gwwiiing *H tha
souixJf. in (ho English language Tho combmaitori of that*
souhda. Pi the order of your chotp
unlimited vocabulary of words, phtaas
won as an *rriy of sound affactm Piggy ^

expandability other modulei log tnomoryl to bo

opotatmg with the Parrot sanultonoously.

'aui Dormafly had (his to toy m tho April tseue of Syntax:

Pocumontanori 4 profesoonei

"Ovarali, R.I.S T i Perrol 4 an aicoHanl unit and per
orrrd up io and bohond my expec let ions “

|iH2M

| [ha smm o*nd ma t. _

Parroili/ Speech Syn
Ihasiiora for my C
2X10 C 2X £
TS1000 at aa plus

■ u m .. kh

M 00 sh/hd

I will also recaiva an axclu-
si ve phrasa tinder pro-
I gram end a 40 page In*
I Uruclion manual, FREE

■ IS DAY MONET BACK
t9Ck j GUARANTEE/C O □
ORDERS ADD It TS
, PAT BY BANK CHECK
I OR MONEY ORDER
1 NTS RESIDENTS
I ADO SW% TAX

Technical Summary

* 12-in. high-resolution phosphorous tube

* non-glare screen and medium-fast (p. 31)
phosphorous persistence

* video band width of 18 MHz to 22MHz

* 80 x 25 character display

* weighs 14 pounds

* 25W at 120V

* 75 ohm negative sync composite video signal input

* 11.9-in. h x 13.6-in. w x 11,8-in. d

* suggested retail price of $79
For more information write to

Leading Edge
do Janet Sarcia
225 Turnpike St.

Canton, MA, 02021

or circle 37 on the reader service card.

Device Delivers

Last month we reviewed
a save/load device design¬
ed to ensure clean, depen¬
dable and accurate loading
and saving of data.
L-Monitor (the company's
and the device’s name)
quickly pointed out to us
that their add-on does the
same.

The L-Monitor features
an easy-to-read microam¬
meter that shows the level
of the recording while
loading or saving. This
meter also allows the user
to adjust the L-Monitor to
work with just about any

tape recorder.

The earphone plug lets
you listen in to the LOAD,
thus making it unnecessary
to unplug the recorder to
hear starting instructions
that may be on the tape. The
L-Monitor can also be used
for aligning the heads on
your tape recorder (a pro¬
blem that will often cause
you great frustration when
you try to load a program
previously saved). The
device comes with com¬
plete and simple instruc¬
tions as well as all
necessary cables.

For more inform a lion, circle 22 on reader service cord.

TIMEX SINCLAIR USER

improves graphics,

USES

1, cleaner* surer loads

2. better saves

3* program duplication
while loading

4. alignment of tape
recorder heads

5, balancing the tape
recorder tone and
volume for optimum use

FEATURES

1* easy to read meters
monitor both save and
load levels

2* earphone plug for listen*
ing or for attaching to an
outside amplifier

3* plugs into jacks on the
computer so the rear
socket remains available
4, Is user-adjustable to
match your tape
recorder
5* simple to use
COST
Assembled

(and tested) . . . . $23.50

Kit . . $17.50

AVAILABLE FROM

L-Monitor

819 Kenyan Lane,

Newark, Delaware 19711
or circle 38 on the reader
service card.

Business/Prof essionol Applications
for Timex/Sincloir users.

Busyness is rhe only publication
geared ro professional & business applica¬
tions for Timex /Sinclair users. Six rimes
yearly busyness presents Feature articles,
New Products Information, Resource List¬
ings . . .and more

Enclosed is my check for Si 2,00 to cover o one year
subscription. Make check payable ro Busyness

Name _ _

Address _ _ _ _

City & Stare _ _ Zip _ _

Busyness P, O. Box 421 770 S. Ft , CA 941 01

For more in/brmotion, circle 23 on reader service card.

Synchro-Sette

The Subscription Magazine for the
SINCLAIR ZX-81 / TS-1000
MICRO COMPUTERS

Games, Educational,
Business, Graphics, Tutorial, Etc.

12 Month Issues —

6 Bi-Month Cassettes

At Least 6 Programs Each

For more irt/tor motion, circle 24 on reader service card-

TIMEX SINCLAIR USER

NOW! A COMPLETE LIBRARY OF
QUALITY SOFTWARE FOR THE
SPECIAL INTRODUCTORY PRICE
OF $19.95

SIMPLEX SOFTWARE INTRODUCES
THE HOME-PAC - 20 PROGRAMS ON
TWO CASSETTES FOR THE 16K TIMEX
SINCLAIR 1000, 1500 AND ZX81.

Now for under $20. you can get a complete collection of 20 quality,
reliable and user-friendly programs on two cassette tapes Although easy
enough for beginners to use, even computer experts will find these pro¬
grams useful. In fact, as useful as other program packages costing
several times more.

Discover the Power of Your Timex Sinclair Computer!

We've developed the programs that you want and need. Useful pro¬
grams to assist you in home budgeting, education and many other tasks.
We' ve also included recreational and utility programs to help you unlock
and explore the power of your computer

The HOME-PAC Contains All tho Following:

1 BIORHYTHMS— Computes and plots four weeks of your biorhythms

2 ANIMALS— Popular artificial intelligence learning game

3 COM PU-S KETCH— Computerized version of popular ETCH-A-SKETCH toy

4 MICRO-ORGAN— 4 octave Organ music through your TV

5 KALE I DOSC RE E N - TV screen becomes a computerized kaleidoscope

6 ADDITION DRILLS— 4 skill levels and scoreboard

7 SUBTRACTION DRILLS— 4 skill levels and scoreboard

0 MULTIPLICATION DRILLS— 4 skill levels and scoreboard
9 DIVISION DRILLS— 4 skill levels and scoreboard

10 COMPUTER AIDED INSTRUCTION- General purpose education
program

11 STATISTICS— Computes mean, variance and standard deviation

12 LINEAR REGRESSION— Computes regression coefficients and displays
equation

13 VECTOR MATH— Adds two vectors and provides resultant vector

14 SIMULTANEOUS EQUATION SOLVER — Solves System of simultaneous
equations

15 CHECKBOOK BALANCER— Reconciles check register with bank
statement

16 NET PRESENT VALUES— Computes net present value of cash flows

1 7 AUTO LOAN ANALYSIS— Computes amount of loan and monthly
payments

18 STAR INVADER— Mini space tnvader game

19 MACHINE LANGUAGE MONITOR— Utility program enters and lists hen
code

20 RENUMBER Utilrty program, renumbers BASIC programs

21 21 PAGE USER’S MANUAL

WE FEEL THAT THE HOME-PAC AT $19 95, WHtCH RETAILS REGULARLY
FOR $29. 95, IS THE BEST SOFTWARE VALUE IN AMERICA .

ADDITIONAL SIMPLEX SOFTWARE PACKAGES

REC-PAC: BIORHYTHMS A ANIMALS Reguiarly $1 1 95. now only $9 95
ART-PAC: CO MP-U-S KETCH, MICRO ORGAN & KALEfDOSCQPE-

Regulariy $1 1 .95. now only $9 95

EDU-PAC 4 MATH DRILLS $ COMPUTER-AIDED INSTRUCTION-

Regularly $1 1 95, now only $9 95

MATHSTAT-PAC: STATISTICS, LINEAR REGRESSION, VECTOR MATH &
SIMULTANEOUS EQUATION SOLVER- Regularly $1 1 95. now only $9 95
RN-PAC: CHECKBOOK BALANCER. NET PRESENT VALUES & AUTO
LOAN ANALYSIS- Regularly $1 1 95, now only $9 95
COMBO: Computerized variation of popular BOGGLE hidden word game with
4x5 game board (2 to 8 players) — Regularly $1 1 .95. now only $9 95

GUARANTEED

All programs are supplied on quality cassette tapes which are guaranteed to
load and run (defective software will be replaced if returned within 30 days)

ACT NOW! OFFER GOOD FOR LIMITED TIME ONLY!

send to.- SIMPLEX SOFTWARE

55 Sutter Street, Suite 623, B-1, San Francisco, CA 94104

PLEASE RUSH MY ORDER □ Please send dealer information
□Check DVISA □ Master Charge

TITLE

PRICE

Shipping & Handling (foreign orders $3)

$1 so

Calif. Res. Add 6.5% Sales Tax

TOTAL

Account No. _ _ _ _ Exp

Name _ _ _ _

Address _

City - State Tip

U.K. Aids the
Handicapped

A series of Microfairs in
the U.K. are being held with
a real difference. These
fairs are set up to show
what is being done in the
field of microelectronics to
help the disabled.

They are called Elec¬
tronic Aids for the Han¬
dicapped and are set up as
mobile units to enable them
to travel across the country.

Timex
Speeds Up

Delivery of the long-
awaited T/S2000 series is
being moved up by Timex,
Demand by dealers and the
public for the new series of
machines has created
pressures to which Timex is
trying to respond.

Originally scheduled as
two machines, the T/S2048
and the T/S2Q72, Timex has
changed this to a single
machine, the T/S2068* in an
attempt to increase its abili¬
ty to put new computers on
the store shelves faster. The
T/S1000 appears to have
lost public appeal and
Timex is working quickly to
replace it with new com¬
puters.

The increase in demand
for the T/S2068 has, it ap¬
pears, not changed the cor¬
poration's decision to also
produce the T/S15G0, an up¬
dated version of the
T/S10GQ. Market analysts
agree that it is imperative
for Timex to get onto the
market with its new
machine quickly if it wants
to maintain its preeminence
in the personal home com¬
puter field.

And Now
the Comics

ecc Publications, the
parent company of Timex
Sinclair User magazine has
come out with another win¬
ner, LOAD RUNNER, which it
calls “the Galaxy’s First
Computer Comic/* Aimed
at nine to 18 year olds, each
comic book presents a
series of stories, puzzles
and news items on such
things as computer infor¬
mation and competitions.

This comic is not Timex
Sinclair specific and in fact

covers just about every
computer available for per¬
sonal home use. The reader
is treated to the adventures
of LOAD RUNNER, the comic
fun of ROM and ram, com¬
puter crossword puzzles
and new stories every two
weeks.

The cost per issue is
about 75 cents. It is current¬
ly available only in the U.K.

0/0

For more in/ormation, cirde 27 on reader service card.

TIMEX SINCLAIR USER

Kwikplot: A program
for investigating correlations

Jim Tankard modernizes and computerizes
a technique devised by British mathematicians

ONE OF THE USEFUL
techniques of statistics is
to look at the relationship —
or correlation — between two
variables. The “variables” are
simply any quantities that vary —
gross national product and literacy
rates, murder rate and number of

in the 19th century

executions, hours spent in exercise
and cholesterol levels, and so on.

The technical name for the
measure of these kinds of relation¬
ships is the correlation coefficient.
This technique was invented by Sir
Francis Galton, a British scientist
who was looking at the relation¬

ships between the heights of
parents and their children as a
means of discovering the laws of
heredity. Karl Pearson, the great
British statistician, realized that it
was a general measure that could
be used to investigate many kinds
of relationships, and developed a

The Kwikplot Program

10 REM " KUIKPL. OT "

20 DIM (17, 25 J
30 LET
J.0 LET MY =0
50 LET CRQSS=0
60 LET MSQX=0
70 LET M5SY=0
30 DIM X(100)

90 DIM V i 1001

100 PRINT PIT 10,0; “INPUT YOUR S
AMPLE SIZE.’*

110 INPUT N
12© CLS

130 PRINT OT 10,0; "INPUT YOUR D
OTP) U ITU EACH X FOLLOWED BY ITS

Y. "

14-0 FOR 1=1 TO N
150 INPUT Xil>

160 INPUT Y (13

170 CLS

ISO NEXT I

190 FOR 1=1 TO N

20© LET MX=MX+XMJ

210 LET MY =MY +Y Ml

22© LET CROSS =CROSS>X ( II *V Ml

230 LET MSQX=MSSX+ (PBS Xfl}}**2

24-0 LET MSQY=MSQY+ (RES YiD) i*S

250 NEXT I

26© LET MX=MX/N

27© LET MY-MY

2 60 LET t ( HS0X /rti — iii.X3 *

2 J

29© LET SY =3 OR ( (MSOY/N) - (MY J **
21

300 IF 5X=Q OR 3Y=0 THEN GOTO 3

310 LET R= ( (CROSS/N) - ( MX +HY 1 1 s i
SXtSYl

320 PRINT ,,MX = " ; MX; ** MY=";MY:"

R = “ ' R

330 IF SX=0 OR SY=e THEN PRINT

"R IS NOT COMPUTABLE”

- 34-0 PRINT

350 LET y.M xtai

36© LET YH=Y(l.i
370 FOR 1=1 TO N

330 IF X ( I ) > XM THEN LET XH=X(I)
390 IF Y i II > YH THEN LET YH =Y C 1 1
4-0© NEXT I

A10

LET

XRBNGE =XH

420

LET

VftfiNSEsVH

430

LET

IX-XRftNGE/16

LET

PsVRflNGE s4-

450

LET

Z =XH

4L0

PGP

£ - L 1" w

470

LET

X t X) = INT ( i CX f 1,1

/XR9NGE

) * 16)

+ 1 * !

460

LET

V i I> =INT ( i (Y ( X>

/Y RANGE

1 *24.1 +1.51
4-9© NEXT I
SO© FOR 1=1 TO 37
510 FOR 0=1 TO 24
520 LET =“ "

530 NEXT U
54-0 NEXT I
560 FOR 1=1 TO N
560 IF ,Y IIJJ=“8-‘

ET R* (X ( II ,Y ( 13 ) = "S"

570 IF fl$(X(I),Y(I))="7“

ET fl$(X(Il ,Y tIJ > ="B"

530 IF A 9 > X ( I ,Y (13 1 ="B“

ET A = iX 1 13 , v s X.» .» =" 7“

590 IF flSUill - Y i I 3 =“S"

ET H = IX ■ 1 3 , v i I.i .5 =“E"

600 IF A$(X(I3 ,Y(I3) =“4."

ET R$ ( X (I) , V (II 1 =" 5 “

610 IF Hj(Xil) ,Y(I.») =”3"

ET AS ? X i I) , y > I » ) -"4-
520 IF iXtl.’ , Y I II J ="£■■

ET A$!X(I3 ,Y (I) 3 =•* 3 “

63G if Aj(X(i),ran=,ii“

ET R* (X Ml ,Y MX J ="2"

64-0 rF A$ (X ill , Y ( I J 1 = " "

ET (X MJ ,Y Ml J =■■*■'

650 NEXT I
660 FOR 1=17 TO 1 STEP -1
670 IF 1 = 1 THEN PRINT "0";rftB 4-

660 ' IF I > 1 THEN PRINT INT (Z+-5
1 ; T R6 Ml

690 LET Z=Z-IX
700 NEXT I

710 PRINT TAB 4-: ” V 11 11 11 I ■

I I

720 PRINT TAB 5,0,7^ iS, INT ft
YRfiNGE— 3*P1 +.5.1 ; TAB 16; INT i (YHfl
NGE-2+P1 +.5J ;TAB 22: TNT \ fYRFHSE
-PJ+.Sl;TRB 23; INT (YRRNGEJ

1 flLN

THEH

THEN

formula for it. The correlation coef¬
ficient gives a numerical measure
of the strength of the relationship
between two variables, or varying
quantities. The coefficient can
range from +1.0 for a perfect
positive relationship to -1,0 for a
perfect negative relationship. A
correlation of or near 0 means that
there is no relationship, or that one
variable cannot be predicted from
the other.

When you are computing a cor¬
relation coefficient, it is also often
useful to look at a graph or scat-
terpJot of the relationship between
the two variables. A scatterplot
represents one variable on a ver¬
tical axis and the other on a
horizontal axis, and contains points
providing a visual illustration of the
relationship. The more the points
tend to form a straight line, the
stronger the relationship,

I developed a program called
KWIKPLOT to construct a scatterplot
and compute a correlation coeffi¬
cient using the T/S10GG ZX81. This
program also computes a mean or

The correlation
coefficient ranges
from - 1 to +1

average for each variable, since this
was easy to include with the other
computations and it can help in
understanding data. These tasks
are easily performed by program
packages such as SPSS (Statistical
Package for the Social Sciences)
available on large university com¬
puters. But it was a bit more of a
challenge to do it with the T/SlOOO
ZX81,

Data are input into Kwikplot with
lines 100 to 160. The sample size is
the number of pairs of observa¬
tions, with each pair being made up
of something like the height and
weight from one case or individual.
The correlation coefficient, along
with the means of each of the two
variables, is computed in lines 180
to 310 and printed in line 320. The
range for each variable is found in

Galton compared
heights of parents
and children

lines 350 to 420. The ranges are
necessary so the computer can
label each axis with a scale of ap¬
propriate values. Lines 430 to 450
determine the values that will be
printed in those scales. Lines 460 to
490 convert the original values of

the X and Y variables to units that
can be graphed on the screen. Lines
500 to 540 create a large array with
17 rows and 24 columns that cor¬
responds to the 17 by 24 character
portion of the screen where points
will be graphed. These lines also fill
the array with blanks. Lines 550 to
650 put an asterisk (*) in the array
at the appropriate place for every
point to be printed. If an asterisk is
already there, these lines assign a 2,
and so on. Lines 660 to 700 print
the labels for the scale for the
X-axis, the line making up the
X-axis, and the points in the scat¬
terplot. Line 710 prints the Y-axis.
Line 720 prints the labels for the
scale for the Y-axis.

The program uses variable names

that are longer than one letter to
help the user understand what is
happening at various places. For in¬
stance, cross is the cross-product
that is a basic part of the computa¬
tion of a correlation coefficient,
and xrange is the range of values
taken by X.

An example of output is shown in
Figure 1. The X-axis (vertical in this
case) lists final grades in a com¬
munication theory class, with the
highest possible score being 75
points. The Y-axis (horizontal in

this case) lists number of absences
during the semester. The lines at
the top print the mean of X (MX),
the mean of Y (MY), and the cor¬
relation coefficient (R). In this ex¬
ample, there is a moderate negative
correlation of -.40 between the
two variables. This correlation sug¬
gests that high numbers of absences
are related to low grades, and vice
versa. However, the fact that the
correlation is moderate rather than
strong suggests that attendance is
not the only variable affecting
grades. Other factors that might
also influence grades are time spent
reading the textbook, skill in taking
notes while attending class, and
time spent going over notes before
a test.

Figure 1. Student grades versus absences from class.

MX. =60 . assays HY =6 . 9655 172 R - 3 . 4-

01692

^55

+ 32

* * 2 2 +

S +3 * * 2 + +

+ + 2 + + **

2 +* * v

4,9

* * **

4.5

* a i ""5

0 S 11 17 22

TIMEX SINCLAIR USER

A second example is shown in
Figure 2. The X axis (vertical) is gas
consumption in a residence
measured in thousand cubic feet.
The Y axis (horizontal) is a time
dimension, with the numbers 1 to
24 standing for a 24-month period
beginning in )anuary. The correla-

MX =7 .3083333 MVsl2.5 R a -0 . 3 14739

4
3

Figure 2. Gas consumption
(vertical) versus time in months.

tion coefficient is probably not very
meaningful here since the
numerical values assigned to the
months were arbitrary and not real¬
ly measuring anything. The scat-
terplot shows that the relationship
between gas consumption and time
of the year has a great deal of
regularity or lawfulness. In this
case, we know that the regularity is
caused by some very lawful
changes in temperature as the
seasons change. But in other cases
that we might not understand so
well, a scatterplot of this type could
help us to discover new types of
regularities, or laws.

KWIKPLOT has limitations. With
certain types of numbers — those
that are more than four digits,
negative numbers, or numbers bet¬
ween 0 and 1 — the scatterplot will
not be printed or will be
misleading, although the correla¬
tion coefficient and means will be

correct. Also, if either X or Y has no
variation, you will get a scatterplot
but there will be a message saying
that the correlation coefficient can¬
not be computed.

The program has several features
that are standard for large com¬
puter program packages but that
might be unusual for small com¬
puters such as the T/SlOOO, ZX81. It
labels the X and Y axes in an easily
readable fashion, and these scales
change according to the value of
each data set. And, as mentioned
before, if more than one observa¬
tion occurs at the same point, the
program prints a number on the
screen instead of an asterisk to
show the number of cases there.

Also, KWIKPLOT is fast. You can
bet that Francis Galton and Karl
Pearson didn’t have anything like it
when they computed the first cor¬
relation coefficients 100 years ago!

©/©

$29.95

Key Features 01 PFDB

1 User irtfodiy menu driven tammand system legiMtt no pewious
CorTipuler knowledge

2 MuHipte *ey searches - A lealure not tound on many mrxe cosily
systems

3 indexing ho* tester rennetal uf data

4 vanatrie tengih I re ids trial dmnnaie rhe guess work required by
marry other systems and saves memory space1

5 VersaiMy - with ds user detinaWe heading1’, and records PFDB

is able lo perform many diHeienl applications
b Deeci execute commands avaitaMe ter experienced users

Personalized Flexible Data Base

<s a sophisticated easy to use Data Base
Management system professionally designed
to allow your home computer to perlorm tasks
that were previously reserved lor more expensive
computers Here are a lew examples of what
PFDB can be used lor

• BIBLIOGfl APH Y/RESE A RCH NOTES

• PERIODICALS INDEX

• PHONE/ADDRESS LISTS

• CATALOG APPLICATIONS: STAMPS.
COINS, ETC.

• AND MANY MORE!

GET THE MOST OUT OF YOUR
HOME COMPUTER WITH PFDB

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NAME

ADDRESS

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ZIP

NEW EXCITING GAME!

BY THE AUTHOR OF
“MR. MUNCHEE”
AND

“SPEED SNAKE”

TS1500
TS 1 000
ZX81
18K

Beautiful Jane has been abducted by savage Kong. Her
rescue requires a perilous venture into Kong's lair (one of 4 ac*
tion structures) during which you will face tumbling barrels,
trap doors, and collapsing girders. Skillful use of the hammer
and broken ladders is your protection. Only great agility and
cunning will outwit Kong — climb quickly or Jane will perish.

* Personalized high score feature
$1 4.95 U.S.A. $1 7.95 CANADA

+ $2.00 shipping and handling. Ontario residents add 7% sales lax.

VISA. MASTERCARD CHEQUE. Cm MONEY ORDER BCCepHKJ
Pot VISA and MASTERCARD include card $, expiry dele, and signature
Send wiih name and mailing address to;

GREG BROOKS SOFTWARE INC.

sox m, postal station a

MISSISSAUGA. ONTARIO
CANADA ISA 2Z6

DEALER AND DISTRIBUTOR INQUIRIES INVITED.

For more inform a lion, circle 30 on reader service curd.

For more information, circle 3t on reader service cord.

Giaasfonf Eiicrson/cs at 3 os font ■ftecTRomcs Gtaoswn f- EttcrRontcs tuapsTom *ucmamc& via os font e it c monies GiaosronE * if ersomes Qiaos ron^ elect names

'et Serious about TS/OOO
'Sf 500/2X81 Computing

ZX FORTH

FORTH is an interactive. compiled language that
expands the capabilities of the TSlOOOand ZXB1 It
has the simplicity ot BASIC but runs up to ten times
faster1 FORTH® most distinctive feature is its
flexibility. Its unit is the WORD. The programmer
can use existing WORDS to define new ones ZX
FORTH has over 250 commands and occupies only
6K of memory. Works on 16 bit numbers, and also
includes some 32 bit arithmetic routines Comes
complete wilh a comprehensive 60-page user
programmer manual.

Z43 529.95

ZX Bug

Machine Code Monitor and
Disassembler

ZXBUG is a power) u i tool for machine language
programming. It is 4K long and uses memory from
71 EO to the top memory ZXBug works in
hexadecimal (base 16). not decimal, so all
addresses are a maximum of 4 Hex bits long.
Provides a total of 26 commands
241 $1 4.95

ZX Assembler

This Machine Code program occupies 7K of
memory and locates itself at the top of memory. The
program is a full Editor Assembler and Monitor
Labels may be used instead of any string. The
features include Line Insertion Delete. Insert
Characters. Auto Repeat on all keys. The monitor
has facilities to inspect memory, registers and run
machine code programs.

Z40 $14.95

Call or write for Gladstone’s

FREE CATALOG

or circle reader service number

New from Gwftlv# Electronics1 Our
ZX|i TStGOG catalog wii Take you
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fontasy and laflNy games business
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Home Computer1 Use me convemenr
coupon and send tor you# FREE
catalog TODAY1

GLaosTont

WATCH FOR NEW TS2000 PRODUCTS!

Fastload

An incredible breakthrough in TSIOOO and ZX81
software development. Enables you to load and
save programs up to 6 times faster than normal You
can easily convert your existing programs into new
I P S FASTLOAD programs And unlike other
systems. NO ADDITIONAL HARDWARE is
required ■ FASTLOAD has won rave reviews from
users, and has proven to be exceptionally reliable in
test after test. Occupies only 1 2K of memory.
Add i tonal features include verification of proper
loading, and catalog of program names and
memory usage. Complete with comprehensive user
manual.

261 $19.95

TOOLKIT

TOOLKIT adds these 9 new. powerful functions to
your computer: Renumbering. Memory indicator,
Print all string and numerical variables Find any
String up to 255 characters long. Replace any string
by any other string. Transfer programs to Ramtop,
Join two programs together. Remove all REM
siatements. Delete whole sections at once
Z42 SI 4.95

Z-AID

Z-AID is a programmer's tool, adding 5 important
functions to TS1000 2X81 computer. VERIFY
checks for corrupted program saves; MSAVE
allows entry to the memory saved using MSAVE:
TPTR allows instant access variables: CHAIN links
two BASIC programs together
Z98 $14.95

The Complete ZX81
and TSIOOO Library!

BOOKS

The Compete TIMEX SINCLAIR I ASIC Learn,
compete wuh Zproqra^ casseiies
Getting Acquainted w*lh you1 ZXBl TSI OOO
ZKBl TSIOOO Pocket Book
Making ihemosl of Vtx ■ ZXBl TSIOOO
Computers lor *'tis ZX8t TSIOOO Ed^on
Enpiomfs Guide to Ihe ZKB1 TSIOOO
ZXBl TSIOOO Companion
39 E «ptod»nq Games tty the ZXBl TSIOOO
Nqi Only 30 Programs In* ZX81 TS1000 IK
Machine Language Made Simple
Masif" ng Mactine Code on your ZXBl TSIOOO
ZXBi TSIOOO POM Disassembly Pans A 6 B
Undemanding yout ZX81 TSIOOO ROM

inq Course
B7f! $24.95

C7CSB95
P 70 $10,95
■ 1 $10.95
C71 $4.94
T 70 $12,95
C72 SB, 95
$1095
B72 $9.95
Bn $14.95
P7 3 $12,95
$1995
676*14.95

Professional ^^$79. 95^^

KE YBOARD with metal case ^AA

TO ORDER CALL

Toll free (800) 833-8400
In N.Y. (716) 874-5510

Have VISA or MASTERCARD ready!

IMPORTANT NOTE AH software products

shown are fully compatible with

Timex Sinclair 1000, 1500, and Sinclair ZX81

A full sized TSIOOO professional keyboard
Features 47 keys and a full-sized space bar
Connects with no soldering required via a
plug -in flexible connector Expansion devices (i e
RAM packs, etc) connect to the ZXBl edge-connec¬
tor which extends from the rear of the cabmel
* American made • Keycap legends will NOT
wear out * Keys with life rated at 20 MILLION
cycles

Keyboard and metal case both for $79.95 kti

GLADSTONE

64KRA

^ ******

Expands in® capacity of the TfS 1000 or ZX81 to its
maximum User transparent

The Complete
Timex Sinclair
BASIC Course

Including BASIC
Course Programs
on cassette tape!

870 $24.95

At last, a comprehensive all-in-one learning
program for your TIMEX SINCLAIR computer
Designed to teach you lo write and develop
BASIC programs — no other books Or aids are
necessary. Every concept, every function is
fully described in a simple program that you can
enter on your computer in minutes The
complete BASIC course is an excellent
reference work for experienced programmers
(including tips on using special techniques and
machine code) as well as a comprehensive
step-by-step guide for complete beginners The
Complete BASIC course has over 240 pages in
an attractive durable ring binder
Price now INCLUDES all major programs in the
BASIC COURSE on two cassette tapes at no
extra charge (formerly S7 50 extra)

GLaOSTOnE-^fELECTROmCS

4COC 1 D.iIIaU kl V

1585 Kenmore Ave. ' Buffalo N.Y. 14217

Have Fun with TStOOO/
T$ 1500/ ZX8 f Computing!

KRAKIT'1 Bored with crosswords? Want a
real mental challenge*? Try solving KRAKIT. the
ultimate adventure and treasure hunt for the
personal microcomputer. KRAKIT consists of 12
clues thai will lead you around the world in search of
12 cities. 12 countries and 12 numbers And if you
are clever enough to be the first to solve these clues,
then you can win at least $20,000 prize money
Each cassette also includes a full sized KRAKIT
poster at no charge*

248 SI 4,95

Computerized Diet Program

Gam control over your eating patterns This is an
individually tailored, systematic weight loss
program. Uses a personal status assessment
Based on your assessment, the TSTOOO ZXfll
becomes your monitor and feedback system,
allowing you to discretely track yourself against your
optimum model Complete with a 22 page Guide
Book, personal data storage tape, and vinyl storage
case 247 $29.95

ZX Scramble You are flying into the heart
of alien territory As you dodge in and out of the
rapidly changing terrain you fire laser rockets and
bombs at the enemy weapons installations They
respond with missiles and flying bombs Destroy
them before they destroy you ?

Z90 $14.95

Business Pac I:

Cash Management

The most needed financial analysis routines for
many business decisions, plus a detailed guide on
how to use them, Five long programs are supplied
on 2 cassettes. Invaluable aid for the business man,
Break Even Analysis Cash Flow Analysis. Payback
Analysis, Internal Rate of Return. Depreciation
Analysis 249 $29.95

Business Pac II:

Project Scheduler & Proposal Sheet.

Time is the most valuable commodity for the
businessman. Project Scheduler helps you keep
track of work in progress and billings in progress
Proposal Sheet is a tool to help you quickly record
work items and hours, billing rates, overheads,
material and labor costs, to finalize your proposals.
250 $14.95

Personal Financial
Planning Pac contains 2 tapes with

a detailed reference flash Instruction manual to help
you gain and maintain control of your personal
finances. The programs include: Checkbook
balancing: Personal Net Worth: Budget Plan (for
home or business): Mortgage Plan,

253 $2995

Personal Stock

Market Planning Contains 4 programs
recorded on 2 tapes, accompanied by a detailed
manual. To help you plan, record and control your
stock market activities These programs have been
adapted for the ZXB1 and TSl 000 from routines
used in large scale computers by a leading software
house. Programs include: Dow Jones Moving
Average. Personal Stock Bond Transaction
Recorder; Portfolio Review, Point and Figure
Z54 $29.95

Now choose
from many
great games!

New So««a'e

Tiny Logo

Let the world of computers become a comfortable
One for your child through the use of this powerful
and fun teaching language In the age of the
computer. Tiny Logo is the key to helping your child
to learn and understand real computer
programming. (Tiny Logo is a sub set of the popular
MIT Logo)

2111 $19 95

Home Money Manager

This complete home budgeting system allows you
1o establish your own budget categories, keep track
of monthly bills and income, and do a monthly and
year end balance sheet No bookkeeping
knowledge is needed
2104 $14,95

Gobbleman Arcade action fun for the
family. A superb realization of this exciting classic
game, showing the true capability of the TS10CK)
and ZX81 computer Written in machine code, this
one is fast, fun and challenging
Z70 $14.95

Run the Country A strategy game of
political and financial management. What would
you do if you ran a country"? Here you can grapple
with problems like inflation "unemployment, foreign
currency exchange It's both fun and educational
Can you do better than the politicians'?

Z77 $11,95

Galaxy Invaders Another arcade
classic, masterfully translated to ihe T51000 and
ZXfh Protect youf seven lives against fleets of
hostile invaders, Fast, exciting and unpredictable

Z91 $14.95

NEWSFLASH; Timex announces new TSl 500 personal computer will run all ZX81 and TStOOO software?

Chess

Master*

Choose from 4 games, for beginner to

Beginner (IK) Chess A single level of piay
miroduces Chess ZS7 $9.95

2K Chess (for unexpanded TS100O) Better
graphics and vastly improved range of moves

Z55 $14.95

Chess I (Enhanced) 16K Full graphics display w«lh
six levels of play Choose black or white Castling
and en passant Save games in progress

Z85 $14.95

Chess II Master The ultimate 16K chess for
TSl 000 7 levels of play Highest raimg by Timex
Sinclair User magazine
286 $24.95

Trader A trilogy of 16K programmes that
combine to give an epic 48K graphic adventure As
a galactic trader, you deal with some very bizarre
customers indeed Will you live to tell the tale'?

PT0 $19.95

Alien Space Ship A long, involving word
adventure ga me for the TS 1 000 and ZX 81 Whileon
space reconnaissance, your ship has been dragged
onto an enemy space cruiser They are intent on
taking humanoid life forms as slaves You must
reach their computer room and release your ship
Fast and varied responses arise and there are many
different ways to win the game
Z61 $14.95

Keys to Gondrun Another involving
fantasy word game in which you travel beneath the
Enchanted Forest in search of the missing keys of
Gondrun the Wizard. Program features real time
monster fights at 6 skill levels There are alternative
responses to ensure a different game every time
Z95 $9,95

Shipping and handling
SOFTWARE. AND BOOKS
add $ l . 50 Fir firsl Mem. SO
oenls for each addiiinnal
item. 1 01 maximum of S&.OOj

HARDWARE: add $100
for first item. $1.00 each
additional item, in a
maxi mum of $6,00.
Maximum shipping rharge

on comhined software,

brinks and hardware order
1$ *■> 00

Sorry no CCDs

We make Computing easy!

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83IUOV1J31* ^uojsaew BMtmiiortt ^ualsael° boiuouidj^ -iuoisaeia soiuomon* -luoisaem aowomaro -suoiBaew sdiuouidh* ^uqisasia boiuouidh* juoisgeio

3-Color Keytop
Legends and
Guide for
Keyboard
Conversion

Simple 11 Lustra ted Instructions will show
you how to convert ft cheap (about $20)
surplus keyboard to a full-size console
(Including automatic -shift functions] .

* Do's and Don’ts for selecting keyboard.

Plastic TS1QQD-ZXB1 symbols for your I
converted keyboard; color -coded; opaque |
background, fit all standard-size keys.
Adhesive backing for easy application. I

Bonus for the *two" - Schematic Diagram |
of Computer. $Q9S*

MULE Electronics

A44 Lincoln Blvd Dapt. 3100
Venice, California 90291

*Add $1.50 F&H. California residents add |
5.5% tax. Money-back guarantee.

For more information, circle 25 on render service cord.

DYNACOMP PRESENTS -

Quality Software for the TIMEX/SINCLAIR

DYNACOMP, the leading distributor of software
for small computers is pleased to announce a
new line of software for the TIMEX/SINCLAIR
computer We examined what the others were
offering, and went two steps beyond*

BLACKJACK $1295

TIC TAC TOE $ 9 95

WORD SCRAMBLE $ 9 95

PIXEL DRAWER $1495

GRAPHICS DRAWER $14.95

CHECKBOOK $1495

DATA FILER $19.95

PHONEBOOK $1295

Order 3 or more and deduct 1 0%; 5 or more, 20%,

A documentation package which covers all of the
above is available for $4.95 (can be applied to the
purchase of any program).

Available on cassette. Requires 16K RAM.
Please include $2.00 for shipping and handling.
N- Y. residents add 7% sales tax. All orders proces¬
sed within 48 hours. 30 day guarantee

DYNACOMP. Inc. Dept. S

1427 Monroe Avenue
Rochester, NY 14610
(716) 442-8960 (24 Hours)

(716) 442-8731 (9 AM - 5 PM EST)

For more inform a I ion, circle 29 on reader service card.

DISCOVER

NEW AND INCREDIBLE

FACTS ABOUT
COMPUTERS!

NEXT MONTH IN
TIMEX SINCLAIR
USER

continued from page ID
reliable tape recorder. While we
make no guarantees, our program¬
mers use the Sears ALC/SLJM
cassette, the Realistic CTR SO, the
General Electric 3-515/B, and say
all work extremely well. So get a
tape recorder and /ill in the sub¬
scription form.

INVERSE VIDEO
CHARACTERS

I just bought the first copy of your
magazine and am very impressed.
The many different departments
with good articles and ideas are ap¬
preciated, T have only one sugges¬
tion so far. When printing pro¬
grams, please include in the text
what the inverse video characters
are. At times it is difficult to deter¬
mine what they are.

James A. Kosinski
Pittsburgh, Pennsylvania

Thanks for the suggestion, James, In
previous program printouts, we
have frequently represented graphic
characters in words. In some cases
this has con/used people. For exam¬
ple, in 16 Pin Bowling fissue #2), we
represented a graphic symbol as
Graphic 1.

We should have described this as
graphic shift 1 to produce the
graphic character on the 1 key. This
method was also used in Lemonade
in issue #1.

zx QUERY

Before I subscribe to Timex Sinclair
User, I need to know how useful it
will be to me, as I have a ZX81, not
a T/S1000.

Kenneth H. Ahrendts

Mingo Junction, Ohio

Good point, Kenneth! The ZX81 and
TISlOOO are virtually the same
machine. The only difference bet¬
ween them is that the ZX81 has IK
RAM while the TISlOOO has 2K.
Everything we publish for the
TISlOOO will work with the ZX81

(keeping the IK difference in ram in
mind]. As well, anything written for
the TIS1500 will work with the ZX81
and TISlOOO if they have 16K ram.
So don't hesitate to subscribe now!

O CANADA

Congratulations on Timex Sinclair
User. I have picked up Issue #3 and
I shall certainly be subscribing.

Two points: Do you have the ad¬
dress for Timex Canada, and is
there a Timex Users Group in Win¬
nipeg or any other Canadian city?

Peter Winter
Winnipeg, Canada

Great to have you as a subscriber,
Peter, You join a huge number of
Canadians who receive Timex
Sinclair User,

To answer your questions: TMX
Canada Inc. is located at 635
Hood Road, Markham, Ontario L3R
4N6, and yes, there are Timex
Sinclair groups in Canada. We do
not have the address of any in Win¬
nipeg but we re sure one of our
readers will send the information to
us. There is a central club called
Timex Canada Computer Club
which can be reached through the
TMX address.

CREDIT WHERE
CREDIT IS DUE

Our apologies to Fred BJechman and
Bill Payne, whose respective bylines
were inadvertently omitted from the
“Binary Banner’* and “Setting
FORTH" articles in Issue 4. 0/ 0

fyttile ta ub

Timex Sinclair User welcomes
reader's comments, compliments,
queries and complaints. Letters
should be addressed to: The Editor,
Timex Sinclair User, 49 La Salle
Avenue, Buffalo, N.Y, 14214. Please
include your full name and address
when writing.

TIMEX SINCLAIR USER

Merging In BASIC

Gary West outlines a technique to do what the T/S manual
says can’t be done — merge sets of data without using
machine or assembler codes

IF you use a T/St 000,1 500, ZX81
for data storage and manage¬
ment, you’ve undoubtedly felt
some anguish at its inability to
merge sets of data. However, in
hacking about with my 8K ROM/16K
RAM, I discovered a method by
which data sets may be merged —
and it’s all done in basic without
the slightest trace of machine or
assembler codes.

My problem developed when I
wished to examine subsets of larger
data sets that 1 had stored on
several separate tapes. From the
larger sets (each of which used
most of my 16K RAM), I pulled the
much smaller subsets and SAVEd
each subset on tape. The total
number of bytes (that is, the
number of letters and numbers) in
the combined subsets was under
8K; so all four subsets could easily
have fit into 16K at one time. But
since each of the four was from
separate programs, there seemed to
be no way to get them together —
unless 1 re-punched three of them
into the fourth.

But with minimal knowledge
about RAMTOP and VARS (the first is
the address of the byte immediately
following the top of RAM, the se¬
cond the address where the com¬
puter begins to store program
variables), I was able to "hide” one
set of data so that LOADing the next
set did not affect the first (and vice
versa). After the second set was
LOADed, the first was moved out of
hiding and I then had access to
both.

After LOADing the first data set,
you will procede through the steps
outlined briefly in Figure 1.

Step

Action

Purpose and Intent

/ind RAMTOP

to know where to begin counting
backward to find your hiding place

lower RAMTOP

to create the hiding place (techniques for
doing so are described JaterJ

/ind VARS

to know where to look for the stuff you
want to hide (you should note that this
address changes every time something is
added to or deleted from your program)

search the files
following VARS

to find the specific address of the first
byte (character) of the data you want to
hide

subtract

to find the number of bytes between VARS
and your data

hide data

to protect it from the dreaded NEW
monster

NEW

to get rid of the program that originally
held your data set; your data are well-
hidden and will not be found by the wild
and rampant NEW

LOAD second
data set

to get second set into the computer (this
has been the easiest step so far, hasn’t it?)

DJM

to create an array that will be large
enough to hold both sets of data

move second
set of data to
new array

to put these data into the new array; then
hidden data will soon be moved to join
these

find VARS

to know where to look for a place where
the hidden data may be moved

search files
following Vahs

to find the address of the last piece of
data you just moved to the new array; the
next byte will be the address to which the
hidden data are to be moved

13 move hidden

data back into
the light

Figure 1

to merge with data that were just placed
in the new larger array

TIMEX SINCLAIR USER

After the final step in Figure 1,
the data are ready to be used,
assuming that both sets were iden¬
tically structured. If not, then step
12 could be a search for the begin¬
ning byte of the old array and the
hidden data could be moved to that
address, resulting not in the merger
of the data into one array but in the
availability of both sets for correla¬
tional operations. Both sets are now
available to have done whatever it
is you wish to do to them.

In order to explain this process,
let’s look at an example that uses
similarly structured data sets: pro¬
gram A has a data array that stores
data in strings (50 strings, each con¬
taining 32 elements: 1600 bytes of
data); program B also stores data in
strings (100 strings with 32

If the hiding place
is too small, data
will be lost

elements each: 3200 bytes of data).
Merging the data sets would permit
better analysis of those data than
would be possible if the sets had to
be examined individually.

After LOADing program A, find
RAMTOP by ENTERing “PRINT PEEK
16388+ 256* peek 1 0369'' as a direct
command. The address of ramtop
will appear at the top of the screen.
Write it on a piece of paper (or COPY
if you have the ZX printer or the
T/S2040 printer). Let’s say that we
get 32000 as the address of ramtop
(I get that address when my qsave
has been previously LOADed; if I
have also LOADed the Syntactic
Sum routine, my RAMTOP is
lowered another 27 bytes).

Since program A has 1600 bytes
of data (in its 50 x 32 array), we will
need to lower ramtop by at least
1600 (we’ll actually lower it by 1650
because problems may result if we
cut things too closely). We, then,
would like to set ramtop at 30350
(that 32000-1650). The trick comes
in telling the computer to do that.

It’s done like this: we found ram¬
top by FEEKing at bytes 16388 and

16389; so if we change the address
stored in those two bytes, we will
have told the computer to change
ramtop. To lower (or raise) ram¬
top, divide 30350 (the desired ad¬
dress) by 256 (which has something
to do with the value of digits 5 to 8
of a binary number); the result is
118 with a remainder of 142; enter
as direct statements, the following:

(a) POKE 16389, 118

(b) POKE 16388, 142
RAMTOP is now at 30350.

dresses; 9920 continues the loop.
GOTO 9900 starts the routine;
remember not to use run because it
will wipe out all your data.

Write the address of the first byte
of the variables file on a piece of
paper.

As the screen fills with addresses
and characters, look for the data
that we will want to hide. When the
screen is full, a code 5 (followed by
a slash and some number) will be
displayed. Press CQNT and ENTER to
continue the data listing.

Now we need to find the address
of the variables file (vars) so that
we can look for the data we*d like to
hide away. The address of the first
byte of the variables file immediate¬
ly follows the program and the
display File (which is the storage
place for things you see on the
screen). The address of that first
byte is important to us because we
can count bytes from it to the first
bytes of our data and can use that
number (with reasonable con¬
fidence) to locate our data even if
the variables file is moved by
lengthening or shortening the pro¬
gram.

To find the address of the
variables file and the address of our
data, we can put the following
routine at the end of our program:

9900 LET M - PE EK 1 6400 + 256 * PEEK
16401

9905 PRINT M

9910 FOR X = M TO M + 3000

9915 PRINT X;“ ”:CHR$ [PEEK X)

9920 NEXT X
GOTO 9900

Line 9900 locates VARS; 9905
PRINTS the address of the variables
file; 9910 starts listing at VARS (the
3000 is a dummy counter); 9915
prints each address and the
character at each of those ad-

4fi

TIMEX SINCLAIR USER

When you have found the data
set, write on a piece of paper the ad¬
dress of its first byte; then subtract
the address at vars from it. The
result is the number of bytes from
the first variable byte at vars to the
first byte of the data set; this
number will allow us to find our
data simply by adding it to
whatever we find when we peek
16400 + 256* PEEK 16401 (regardless
of how that address changes).

As part of our example, let’s say
that the address at vars is 17337
and that we find our data at 18357.
The difference is 1020; so our data
will (as stated earlier, “with
reasonable confidence”) always be
1020 bytes beyond the beginning
address of the variables file. Our
data (which, if you remember back
to last week when we started all
this) contains 1600 bytes; so the ad*
dress of the last byte of our data
will be VARS + 1020 + 1600 - 1 (we
have to subtract 1 because the first
byte is at 1020 beyond vars and not
at 1021 beyond that address).

Now that we know where our
data are and where the hiding place
is (above RAMTOP), all that’s
necessary is to move the data to the
hiding place. To do that, replace
lines 9905 through 9920 with the
following routine (leave line 9900
as previously entered):

9900 LET M - PEEK 16400 + 256* PEEK
16401

9905 LET XX -30350
9910 FOR X “ {M + 1020) TO
(M + 1020 + 1600-1)

9915 LET XX- XX + 1
9920 POKE XX.PEEK X
9925 NEXT X
GOTO9900

Line 9900 locates VARS; 9905

starts at ramtop; 9910 starts listing
at the First byte of the data set; 9915
goes to the next byte in the hiding
place; 9920 hides each byte of data
above RAMTOP; and 9925 continues
the loop. Use GOTO 9900 to start the
routine and, again, remember not
to RUN anything.

The data set is now hidden,
beginning at 30351.

Enter NEW in order to get rid of
the program that had originally
held the data set. Because we have
hidden the data set above ramtop,
the NEW command cannot find it to
wipe it out.

load the second data set in the
normal manner. Our second data
set (you will recall) contains 3,200
bytes in a 100 x 32 array. In order
to merge these data with the hidden
data, we must create an array that
is large enough to hold both. We
would need to add the following
line to our program:

9900 DIM B$( 150,32)

GOTO 9900

The GOTO 9900 will establish the ar¬
ray we need. After that is done,

You must “hide”
one set of data
before loading
another

delete line 9900 (by ENTERing 9900)
so that there is no chance of ac¬
cidentally erasing our data set.

Please note that the use of B$ is
predicated on the assumption that
the second data set is not B$; let’s
assume that our data are in
A$(100,32). The following Lines will
move the data in A$ to B$;

9900 FOR X - 1 TO 1QD
9910 LET B$(XJ-A$(X)

9920 NEXT X
9930 DIM A$[0,0)

GOTO 9900

Line 9930 wipes out the old A$ so
that there is no chance of confusing
A$ with B$ when we begin looking

for the specific address of our new
data array (B$).

To find B$ in the variables file,
place the following lines at the end
of the existing program:

9900 LET M- PEEK 16400 + 2S6*PEEK
16401

9910 PRINT M

9920 FOR X-M TO M + 3000

9930 PRINT X;“ ”;CHR$ (PEEK X}

9940 NEXT X
GOTO 9900

Write the value of M on a piece of
paper before beginning your search
for B$. You might wish to refer to
the comments that follow the
similar routine described earlier.

We are now going to look for the
last piece of data that was put into
B$ because we want to move the
hidden data so that it follows the
existing data in B$. The hidden
data will be moved to fill the re¬
mainder of B$.

Continue your search until you
have found the address of the last
byte of data. The next byte is the
location at which the hidden data
are to begin. But the displayed ad¬
dress may not be the proper ad¬
dress when the routine is added to
move the hidden data (remember
that vars moves as program lines
are added or deleted). In order to
locate this address later, we need to
determine how far this address is
from the beginning of the variables
file. Later, by adding that dif¬
ference to the vars pointer, we can
— with reasonable confidence —
find the proper byte for moving our
hidden data. For our example, let’s
assume that the difference is 2337
bytes.

In order for the computer to
know how to treat the hidden data
after they are moved out of hiding,
those data must be moved into an
array that has been previously
designed for accepting those data
(that’s the reason we DtMmed B$). If
the data are moved into the
variables file without being made
part of an existing array, the com¬
puter will not know what to do with
those data because the necessary
pointers and other things will be
missing; thus, you can see the im-

TIMEX SINCLAIR USER

save the merged data
as soon as the merger is completed

portance of adding to the data we
moved into B$ and you can see the
reason for making room in B$ in
which to put the hidden data.

Now we know where we want to
put our hidden data and we know
where we hid it. The following
routine will bring the data out of
hiding and will place it in the array
created earlier:

9900 LET M = PEEK 16400 + 256* PEEK
16401

9910 LET XX- 30350
9920 FOR X = (M + 2337] TO
(M + 2337 + 1600-1)

9930 LET XX = XX +1
9940 POKE X.PEEK XX
9950 NEXT X
GOTO9900

To check that your data are correct¬

ly merged, add the following lines:

9960 FOR X - 1 TO 150
9970 PRINT B$(X)

9980 NEXT X
GOTO 9960

The two sets of data are now merg¬
ed into one array. Now you are free
to do all those things that typically
— though accidentally — happen to
damage data sets.

Please remember to SAVE the
merged data as soon as the merger
is completed.

Let's review some of the areas
where problems can be anticipated:
(1) You must find the beginning of
the data set you wish to hide and
you must reference it in terms of its
distance from the address of the

first byte in the variables file since
that address changes as your pro¬
gram is lengthened or shortened. (2)
The same is true when you are
searching for the end of the second
data set (to which you wish to
merge the hidden data set). (3) You
must create a hiding place large
enough to hide your data set or
some of those data will be lost (or
worse, altered). (4) When SAVEing
your data to tape, remember that
anything you've hidden away will
not be SAVEd. (5) Remember to
move ramtop back to its original
location so that you will have plen¬
ty of RAM in which to perform the
“correlational operations" men¬
tioned earlier (such can be done by
FQKEing into 16388 and 16389 as
described earlier). It is now up to
you to use your best modular pro¬
gramming techniques to get the
most from all the work done in
BASIC merging. @/0

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Britain’s Software Pioneer
Days are Over

THE OLD pioneering semi-
amateur days of the
Sinclair market in Britain
are rapidly coming to an end It is
still possible for someone with a
good program to start selling
cassettes in a small way and build
up production slowly, usually
working from home, but no longer
is it an easy way to a fortune.

The market has become more
sophisticated and the selling of a
good cassette can be just as difficult
as writing it.

It is a move which has been ex¬
pected for some time, the only ques¬
tion being whether it was going to
follow the example of the record or
the book markets. The recent
launch here of Virgin Games, a sub¬
sidiary of Virgin Records, gave an
example of what might be expected
if the route was to be that of the
record industry. The event took
place in a club in London with loud
music, large crowds, a Maggie
Thatcher impersonator and, almost
as an afterthought, the games being
shown and their young writers
wandering around looking a little
lost in all the commotion.

Other record companies which
have shown an interest in selling
programs for the Sinclair machines
are K-Tel which has just signed a
deal with DK Tronics and Thorn-
EMI. Despite the involvement of
these companies, it seems more
likely the book model will be the
one which is followed, with the
work split between publisher,
duplicators and distributors.

Many of the larger companies
which began by writing their own
programs in the early days of the
ZX81, such as Bug Byte and
Quicksilva, are now moving into
the area of publishing. They are tak¬
ing more and more programs from
outside writers and doing the
marketing for them.

Cassette distribution is also im¬

proving fast. Mail order has been
losing its dominance ever since
W.H. Smith, one of Britain's major
news agents and stationers, began
selling cassettes. Other major retail
chains were slow to follow but now
many software houses are signed
up with distributors, and retail
sales through shops will soon

Will programs be
marketed like
records or like
books?

become accepted as the normal
way of obtaining new programs.

Prism Microproducts has been
one of the leaders in expanding the
retail outlets. A sister company of
ECC Publications which publishes
Timex Sindair User, Prism has
signed a deal with Rumbelows, a
nationwide chain of electrical
retailers, to begin a rack jobbing
system. Rumbelows' shops have

WINDOW

special displays which are serviced
regularly by Prism employees,
replacing stock which has been
sold and taking out slow-moving
cassettes and putting in new ones.

The company is also looking at
alternative distribution systems. It
has been appointed exclusive
distributor for Romox in the U K.
Romox is a California-based com¬
pany that has developed a system for
selling games on cartridge. Each
retailer has a terminal which allows
cartridges to be recorded in the
shop, using either a blank tape or
one that has been erased. It allows
the retailer to carry no stock other
than blank cartridges, and the
distributor can immediately make
new games available by putting
them on the terminal.

The system is not yet available for
the Sinclair machines, but if a test
market being done in Birmingham
in the autumn proves successful, it
cannot be long before it arrives.

The effect of these changes has
been to raise the threshold of enter¬
ing the Sinclair market. It is still
possible to follow the amateur route
of writing a program and selling it
through a small advertisement in
Sinclair User. This will no doubt
continue to prove profitable but for
a program to make really large
sums it will now need a major
launch. Without strong financial
hacking and a supporting catalogue
of other software that would not be
possible.

While there are many people who
have been involved with Sinclair
computers since the early days of
the ZX80 who are a little sad that
the old easy-going times may be
over, it is recognized that it is a
change which must happen if home
computing in Britain is to become
a major leisure industry in the
next few years. 0/0

— Nigel Clark

in London

TIMEX SINCLAIR USER

Locking

How to prevent nosey people
from l.OADing your programs?

On your 16K machine, type in:

POKB 16386.255
POKE 18389,127
NEW

POKE 32767. n

This sets RAMTOP down 1 byte;
the secret code number “n” may be
any integer in the range 1 to 255 ex¬
cept 62.

Now type in or load the program
to be protected and add the follow¬
ing lines:

9960 STOP

9970 SAVE "program name"

9980 IF PEEK 32767 <> n THEN
RAND USR 0
9990 GOTO start

To save, type

To load, do step 1 and load nor¬
mally, If your code number n is at
32767 the program will run
automatically; otherwise it will
vanish without a trace because
usr 0 has the same effect as pull¬
ing out the power supply* Don’t
forget your code number!

Values for other memory sizes;

16K

POKE 16388

255

POKE 16369

67 .

127

Code Addr.

17407

' "l1 4 '

16431

32767

ramtop may, of course, be set to
any lower value.

— Thomas Bulloch

Saving

Memory

Two methods of memory saving
coding are the use of CODE to assign
or test for many variable values bet¬
ween 0 and 255, and pi-pi for the
value of zero* To see the relative
value of these two as memory
savers I tried the following pro¬
grams* The idea was to initialize
the value of four variables, A,B,C,D
to 0, Not shown is line number 99
which prints the size of each pro¬
gram* It is:

99 PRINT "CODE LENGTH IS"; PEEK
16396 + 256 * PEEK 16397 - 16560

Here are the results:

10 LET A * 0

20 LET B - 0

30 LET C - 0

40 LET D - 0

10 LET A » 0

20 LET B = 0

30 LET C * 0

40 LET D - 0

Takes 60 bytes

Takes 54 bytes

10 LET A - PI-PI
20 LET B * PI-PI
30 LET C - PI-PI
40 LET D - PI-PI

10 LET A = 0

20 LET B = A

30 LET C - A

40 LET D - A

Takes 44 bytes

Takes 42 bytes

10 LET A = PI- PI
20 LET B ^ A

30 LET C “ A

40 LET D - A

10 LET A - CODE ""
20 LET B - A

30 LET C - A

40 LET D = A

Takes 36 bytes

Takes 38 bytes

As you can see, the use of these
techniques can save that extra byte
or two to squeeze those display
burdened programs into your
budget bound RAM*

— Chip Hacker

RAM Pack Wobble, Solution 17

Blue No More

The following tip comes from a
reader in Clay, New York:

“It was with considerable in¬
terest that I read about the “ram
pack blues11 in the Hints £r Tips sec¬
tion of Issue #1. I purchased a
T/S1000 and 16K ram for my nine-
year-old son, and he soon attained a
state of total frustration because of
its erratic behavior. I myself spent
many late hours trouble-shooting,
thinking the problem might be tied
to certain programming routines
indicating a fault in the chip* Even¬
tually I stumbled upon the obvious:
the imperfect connector system for
the ram*

TIMEX SINCLAIR USER

VI'

i fink ■

Copying More
or Less than
the Standard
22 Lines

Those who own the ZX or Timex
Sinclair printer have probably
found that the COPY function copies
the 22 lines of the screen normally
used by the computer. What do you
do if you want to COPY only the top
10 lines or the entire 24 lines of the
screen? You end up wasting 12
lines of paper in the first case, or
having the bottom of your display
copy left uncopied in the second.
This short, simple machine code
routine allows you to specify the ex¬
act number of lines you want
copied.

The COPY routine in the Sinclair
ROM starts by loading the D register
with the number of lines to be
copied. In this routine, we just load
the D register with the number of
our choice and jump to the rest of
the COPY routine (088B).

Enter the following program:

1 REM (five spaces long)

10 POKE 16514.22

11 POKE 16515,10

12 POKE 16516,195

13 POKE 16517,107

14 POKE 16516,6

Run the program. The listing will
now look like this:

1 REM

10 POKE 16514,22

11 POKE 16515,10

12 POKE 16516,195

13 POKE 16517.107

14 POKE 16516,8

Delete lines 10, 11, 12, 13, and 14.
They are no longer needed. The
machine code has been installed in
the 1 REM line.

Now try writing the following
program:

1 REM

10 FOR N - 0 TO 21

20 PRINT N

30 NEXT N

40 RAND USR 16514

The screen’s lines will be
numbered 0 to 21, but when the
program reaches 40 RAND USR
16514, only the first 10 lines of the
screen are copied.

The machine language program
is:

D&cfmoJ Mnemonics Hex

22, n LD Dtn 16, n

195, 107, fl JP Q86B C3, 6B, 06

The character n in the first in¬
struction is the number of lines of
the screen that you want to have
copied. The number can easily be
changed by PGKEing 16515 with
another number. Any number bet¬
ween 1 and 24 can be POKEd.

The routine can be called by
RAND USR 16514.

Should you want to print on all
24 lines of the screen as well as be¬
ing able to copy all 24 lines, just in¬
corporate in your program, POKE
16418,0. You will be able to PRINT
on the bottom two lines of the
screen. The command POKE 16418,
0 must be incorporated within the
program; it has no effect if done in
the immediate mode. If you have
POKEd 16418 with zero, you must
POKE 16418 with a 1 or 2 prior to an
input of a variable; a crash is
guaranteed otherwise. An alternate
way of entering variables when you
are using all 24 lines of the screen is
through the use of inkey$. 0/0

— David IV. Hoshor

“My solution is considerably less
expensive than various products
that sell for as much as $35.95. Very
simply, I have found that a large
rubber band does an admirable job
of securing this connection. I have
been utilizing this system for over
five months (yes, I also enjoy this
remarkable computer); I am on my
second rubber band as the First fail¬
ed after four months. My son is
now thoroughly enamored with
the world of computers.

*T considered taking an ad in
Timex Sinclair User to offer this
revolutionary product For, say,
“$5.95 + postage” to one and all,
but decided that doing so would be
'highway rubbery.1 So I freely relin¬
quish all rights to this idea to the
users and owners of T/S 1000s and
ZXBls around the world.”

— John M. Thompson, Jr.

PHOTOGRAPHY * Bemie Prosl

TIMEX SINCLAIR USER

PHOTOGRAPHY * Bill Dennii Krill, Bmd Bennetl

ttfvt $ rcu*>s

T/S Entrepreneurs

Dennis J. Krill of the Central Pennsylvania group describes
the products that originated within his group

THE Central Pennsylvania
Timex Sinclair User Group
meets for about two and a
half hours each week. We en¬
courage open discussion on all
levels, from beginner to expert, for
there is no better way to educate
everybody. Our membership cur¬
rently numbers about 120.

The unique aspect of our group is
the amount of innovation that has
resulted from our discussions. All
members benefit from experimen¬
tation resulting from questions.

Bill Russell, for instance, has
developed hardware that not only
filters the signal between the
machine and tape recorder, but vir¬
tually guarantees a good load every
time. The large amount of requests
for his Winky Board forced him to
start his own company (G. Russell
Electronics) in order to manufac¬
ture Winky Board II. The device
was the result of the question,
"Why do I have so much trouble
when loading programs from
tapes?*" But Russell is not limiting
himself to one item. He is currently
developing a Winky Board that will
operate with ID tape recorders (for
commercial use) as well as a line of
software.

The experimentation of Brad
Bennett is also providing benefit to
all users. His ZXLR8, available from
Advanced Interface Designs [his
own company), will raise the baud
— the speed at which the machine
accepts information. His method
will load from a tape recorder six
times faster than normal. Bennett
has produced two items that will
achieve this result: (1) software
tape, and (2) an eprqm that is piggy¬
backed onto a chip located on the
machine circuit board.

Bennett did not stop there. His in¬

quisitive nature led to the develop¬
ment of a high resolution graphics
board. With this hardware, he is
able to display, among other things,
a histogram which would aid his
development of a speech recogni¬

tion module. At a recent meeting,
he demonstrated his machine's
ability to recognize the spoken
word by correctly displaying any
word previously programmed. For
instance, one member programmed
his histogram for numbers from
one to 10. He then randomly chose
a number and spoke into a
microphone. To the amazement of
all, that number was printed onto
the television screen by the com¬
puter. The same result was ac¬

complished with words,

John Kennan, who until his pur¬
chase of a ZX81 kit was a relative
newcomer to computers, has
developed a series of software
routines to aid his programming ef¬

forts, Key allows the user to stop
and list machine code programs.
Using the ‘protect* and ‘merge* se¬
quences, a user can store a program
above ramtop while working on
another program, Kennan’s
background in chemistry requires
this capability to be incorporated
into his programming. However,
members from other disciplines
have utilized Key in their work. Key
is also available from G. Russell
Electronics,

Brad Bennett (le/ty and Roger DeAngelis look on as
Dennis Krill (center] makes the /Inal connection to
his inverse video modification.

TIMEX SINCLAIR USER

HU '/>

Roger DeAngelis's background in
statistics brought about his sift i
and SIFT ii packages. This software
will not only perform statistics
calculations and plots but will also
educate a user with no previous
statistics knowledge. DeAngelis
wrote his programs in a compress¬
ed form to allow them to be run on
a 2K base machine. Included with
his package (available from Com-
pucraft) is a thorough manual.

Bob Heil is currently preparing to
teach a Beginner's Course — based
on the T/S1000 at a local business
school. Heil has been using the
computer for only six months.

Many of the members have not
only wired their own typewriter-
size keyboards but are also
customizing this hardware by ex¬
perimenting with special dedicated
keys. We have found this capability
necessary when we run our own
programs. Specific uses are; single
key edit, delete and arrows (no need
to press shift); calculator style
number pad; and user defined func¬
tions. Some have developed a
"plug-in'* technique using dip
sockets. This affords use of the
large keyboard while maintaining
the portability of our machines.

Dennis Krill (graphics
background) required an inverse
video capability in order to cut
down on eyestrain while drawing
on the screen. Internal addition of a
circuit board along with modifying
the video output to uhf has cleaned
up his display. Other members are
now making similar modifications.

A most unique innovation has
been devised by Rich trace. A stu¬
dent at Lock Haven State College,
I race installed a T/S1000 into a
robot he is constructing for an
engineering class. Included will be
a speech module. When the robot
“talks” a series of leds will blink to
give the appearance of a mouth
opening and closing.

In order to maintain communica¬
tion with other user groups,
publications and manufacturers,
our group produces a monthly
newsletter, Synapse, in which we
publish programming tricks and

One group
member is
developing a
speech recognition
module

discoveries, software and hardware
reviews as well as interesting
routines that might be useful to
others. We consciously attempt to
share information so that others

may benefit from our discoveries.

Our library contains 75 pro¬
grams, 12 books and a complete
collection of available T/S,ZX
related publications. With this in¬
formation, an individual can test an
item before spending money on
something that will not satisfy his
needs.

To date four companies have
developed from our group. They
are G. Russell Electronics, Advanc¬
ed Interface Designs, Compucraft
and Kennan Software. We are
always interested in hearing from
other user groups.

Scenes from the Pennsylvania group (clockwise from lop); Bill Bussell operating
Roger DeAngelis1 work center; Dennis Krill using DeAngelis' /ulJ-size keyboard and
equipment to test a graphics idea; Katie DeAngeJ/s demonstrating a program.

TIMEX SINCLAIR USER

14 fi'*ufs

National Listing

Is your group included?

ARIZONA

Timex/Sinclair Users' Group
of Tucson
RO, Box 41795
Tucson, AZ 85717

CALIFORNIA

Bay Area ZX User Group

2660 Las Aroma

Oakland CA 94611

Feather River User Group

Plumas County

RO. Box Z80

Storrie CA 95980

Pacifica TS/ZX Users’ Group

263 Gateway #107

Pacifica CA 94044

Contact: George Mockridge

415-359-3198

Peninsula Users Group

Peninsula Hospital Meeting

Rooms

1783 El Camino Real
Burlingame CA
Contact: James
415-357-5863

Perkin-E Inter Users’ Group
8333 Pumalo
Alta Loma CA 91701
Contact: Rein Smith

South Bay Computer Club
2316 Walnut Ave
Manhattan Beach CA 90266
Contact: John W. Petersen
213-545-9581

South Bay Timex/Sinclair

Users’ Group

947 Clara Drive

Palo Alto CA 94304

Contact: Paul Perreault

The Sinclair Group

1400 Guerneville Rd Suite 11

Santa Rosa CA 95401

Contact: Thomas C. Whitson

West LA, Sinclair/Timex User

Club

P.O. Box 34545
Los Angeles CA 90034
Contact: Dr, George Kuby
213-550-5035

COLORADO

T/S Users Group

Mile High Chapter
12026 W. Virginia PL
Lakewood CO 80228
Contact: Peter J. Callinicos

CONNECTICUT

Sinclair/Timex Users’ Group
1070 So Colony Rd,
Wallingford CT 06492
Contact: Carol Doyle
203-269-7595

WASHINGTON OX.

Washington Area Users
RO, Box 6239
Washington D.C. 20015

FLORIDA

Compu-Pal International
Box 5330 Suite 400
Spring Hill FL 33526
Florida Suncoast T/S Society
P.O. Box 5021 -U
Spring Hill FL 33526
Contact: John Dowlan
904-683-3961
Sam-Bam Users’ Group
P.O. Box 596
Safety Harbor FL 33572
Contact: Mel Routt
Sinclair/Timex SE Region
Newsletter
869 Levitt Parkway
Rockledge FL 32955
Contact: Ralph M. Coletti
305-853-6901

Space Coast Microcomputer
Club

70 Darwin Ave
Merritt Island FL 32952
Contact: Bruce H os ken
Timex And Sinclair Bay Area
Microcomputer User’s Group
[TAS BAM]

P.O. Box 644
Safety Harbor FL 33572
ZX/Timex Users' Group
950 Cynthia Drive
Titusville FL 32780
Contact: John J, Renaud

GEORGIA

Atlanta Users’ Group

P.O, Box 2842
Atlanta GA 30301
Contact: Phil Hoffstadter

T.U.G, Timex User Group of
Marietta Georgia
3105 Mary Dr. N.E.

Marietta GA 30066
Contact: Hubert Crowell

ILLINOIS

Chicago Area Users' Group
323 S. Franklin #804
Chicago 1L 60606
Contact: Larry Weigel
Circle Chess Group
RO. Box 63
Des Plaines 1L 60017
Contact: A.F. Stanonis
Sinclair Users' Network
2170 Oak Brook Circle
Palatine IL 60067
Contact: Diana Wright
312-934-9375

INDIANA

Sinclair Midwest Users’
Group

P.O. Box 13042
Fort Wayne IN 46866
Contact: Robert C. Carroll
White River Computer Group
210 Kingsbury Ct,

Anderson IN 46014
Contact: T. Ondecker

LOUISIANA

Gulf Coast Sinclair Users’
Group

144 Terry Dr.

Slidell LA 70458

MARYLAND

Amateur Radio Group
5448 Tilden Road
Bladensburg MD
Contact: Jim Wallace
Prince George’s Sinclair
Users’ Group
5448 Tilden Road
Bladensburg MD
Contact: Jules Gesang
301-243-2550

Seabrook/Lanham Sinclair
Users’ Group

9528 Elvin Lane
Lanham MD 20706
Contact: Cora C. Dickinson
MASSACHUSETTS
Boston Computer Society
3 Center Plaza
Boston MA 02136
Contact: Sue Mahoney
Mitre Bedford Sinclair/Timex
Computer Club
Box 208, El 70 Mail Stop
Bedford MA 01730
Contact: Ed Lindsay
MICHIGAN

Michigan Area Users’ Group
433-D E. Edgewood Blvd.
Lansing MI 48910
Price’s Users' Group of
Michigan
P.O, Box 651%

Rochester Ml

Contact: Kenneth M. Price
313-651-4475

NEBRASKA

S.U.N, (Sinclair Users’

NetworkJ

4903 Walker

Lincoln NE 68504

Contact: Patrick Murphy

402-464-8086

NEW HAMPSHIRE

CQZX

Amateur Radio Users
11 Briand Drive
Nashua NH 03063

NEW JERSEY

Bayshore T/S User Group
100 Klean, Inc.

P.O. Box 49
Matawan NJ 07747
Contact: President R. Burke
Mawby

NEW MEXICO

Timex/Sinclair Users’ Group
of Albuquerque
1233 Sandler St N.E,
Albuquerque NM 87112
Contact: Carl Miles

NEW YORK

Data America Computer
312 E, 84 St. #1A

TIMEX SINCLAIR USER

New York NY 10028
Finger Lakes Timex Sinclair
User Group
do Mark Tepper
67 N. Main St.

Geneva NY 14456

Sinclair Computer Users'

Society

P.O. Box 36

Johnson City NY 13790

Contact: Paul A Hill

Upperstate New York ZX01

Users

13 Dennis Ave
Plattsburg NY 12901
Contact: Vern Olsen
ZX Users' Group of America
626 Water St.

New York NY 10602
ZX Users' Group of New York
Box 560 Wall St
New York NY 16005
Contact: Caroline Vivanco

NORTH CAROLINA

Triangle Sinclair Users'

Group

do Douglass Dewey
206 James St
Carrbord NC 27510
Triangle Sinclair Users1
Group

PO Box 12546

Research Triangle Park NC

27709

Contact: John Drummond
916-543-8006

OHIO

Timex/Sinclair Users* Group
of Cincinnati
11 Funston Ln
Cincinnati OH 45210
Contact: Rick Johnson
513-025-1449
PENNSYLVANIA
Central PA TS/ZX Users*
Group

RD 1. P.O« Box 539
Center Hall PA 16828
Contact: Bill Russell
814-364-1325

Pittsburg Area Computer Club
Special Interest Group —
Sinclair

1605 Middlecrest Drive
Glenshaw PA 15116
Contact: Dick Welsh
412-487-0789

TENNESSEE

Chatanooga Area Sinclair
Users

P.O. Box 1321
Coilegedale TN 37315
Contact: Dan Williams
TEXAS

Houston [West! Timex/Sinclair

Users’ Group
13327 Rain Lily Lane
Houston TX 77003
Contact: David C. Bonner
Timex Educator's Users*
Group School of Education
Texas Wesleyan College
Fort Worth TX 76105
Contact: Mark Wasicsko
017-531-4440

VIRGINIA

Central Virginia Users' Group

Rt h Box 192

Troy VA 22974

Colonial Pennwild TS User

Group

146 Hawthorne Drive
Newport News VA 23602
Contact: Jim Langston
804-077-3920

The Franklin County Sinclair
Local User Group [SLUG]

Rte I Box 21
Glade Hill VA 24092
Contact: Gary Preston
WEST VIRGINIA
Sinclair Super Group
949 Brier St.

SL Albans WV 25177
Contact: Wm M eel aw 0/0

T/S1000.ZX81

USER GROUP “BONUS BUCKS” OFFER

EARN AT LEAST
$125

FOR YOUR GROUP

TAKE THESE FOUR STEPS AND EARN "BONUS BUCKS”

1. Sign up to 25 members or more as subscribers for
Timex Sinclair User magazine, at $29.95 each.

2. Send us a check for only $24.95 per order.

3. Keep the $5.00 Cash Bonus for each order. (Minimum
25) Earn at least $125 for your group.

4. Send us the names and addresses of the subscribers.

USE YOUR CASH BONUS TO:

* Pay for your newsletter * Purchase machines

'Hire speakers for meetings * Rent meeting halls

Please send subscriptions to our
user Group Members

_ Members @ $29.95

Deduct $5 per member - _

Send check for _

Your Club Keeps The Difference /

Mali to:

Timex Sinclair User
USER GROUP OFFER
49 LaSalle Avenue
Buffalo, N.Y. 14214

FREE

‘PACKRABBIT’

Retail value $15.00

A good reason to order now!
Receive a software program
cassette of an exciting, new ar¬
cade gamel “Packrabbir is a
regular $15.00 retail value. Free
with subscriptions for a limited
time only.

TIMEX SINCLAIR USER

The ariides in this series are excerpts /ram the book,

“Programm ing Arcade Games/' soon to be published by
Heston Publishing of Heston, Virginia.

Part I of a new five-part series
by Bob Fraser

Programming Arcade Games

THE computer language
basic is a summarized, user-
oriented system which per¬
mits you to communicate easily
and painlessly with the computer.
Each command in BASIC is
translated by the machine into a
series of primitive instructions
known as machine code. Groups of
these instructions performing
specific functions are called func¬
tional groups or macros.

Thus the print statement in¬
volves a series of machine code
operations enabling the required in¬
formation to be displayed on the
screen.

We now can see that BASIC
simplifies program writing and at
the same time increases program¬
ming speed. However, because it
involves commands that require
further internal code, the execution
time suffers. Programming ease has
increased at the expense of speed of
program performance. This is ap¬
parent in a comparison of screen
movements using BASIC and
straight machine code.

Still, the speed of movement in
BASIC is quite sufficient for many
game and program applications.

BASIC: Fast to program but slow
to move.

Machine Code: Slow to program
but fast to move.

There are three methods to move
objects on the screen: using the
PLOT/UNPLOT statements; using the
PRINT AT statements; using PEEKS
and POKES and system variables.

PLOT/UNPLOT statements are

used in conjunction with a single
picture element called a pixel. For

the standard T/S1000, ZX81, the
screen is composed of 64 x 44 pixel
positions.

To access a location, type in the
co-ordinates of that location (To
designate co-ordinates, specify col¬
umn and then row.) Thus, to plot a
point at (3,2), type PLOT 3,2. To
erase this point, type UN PLOT 3,2,

The columns across have one ex¬
tra non-printable position called
the ENTER character. Its use will be
described later.

Type in

10 FOR 1 = 1 TO 20
20 PLOT 1 + 4
30 NEXT I

and run it. What you will observe is
a straight line being plotted across
the screen at Y = 4 and X = 1 to 20,
one point at a time.

Add this statement to your pro¬
gram:

15 UN PLOT 1-1,4

and run it once again. What you
now observe is a pixel moving in¬
dividually across the screen — in
other words... animation!

Unfortunately, the motion is very
slow and limited to the specific
shape of the pixel. However, you
have now seen the underlying prin¬
ciple of moving an object across the
screen; printing it and then erasing
it through consecutive points. This
is very similar to the apparent
movement of lights on an electric
sign — the lights simply go on and
off in succession to create the illu¬
sion of movement.

For practice, try producing a pix¬
el that moves down the screen or

back across the screen in the other
direction, (Hint: Erase behind the
pixel by erasing the I + 1 position.)

PRINT AT statements are far more
powerful than PLOT/UNPLOT
statements because they allow for
different characters to be printed,
and you can create faster
movements.

The plot statement is slower
because it involves a large group of
subroutines that are used to create
the continuity of the small pixel.
The print AT statement avoids
those subroutines. The actual small
graphics character (first four il¬
lustrated characters) is not part of
the character set available to the
user. Thus to create a line of pixels,
the machine code subroutines of
plot statement must calculate grid
positions and combine the standard
graphic characters to produce the
desired continuity.

□ a h h a

■ ■ ■■ ■

The overall effect is a motion that is
slow, made so by the extra time re¬
quired to run those subroutines.

PRINT AT 3,2 prints on the third
row down and the second column
across.

Type this short program in:

10 FOR I * 0 TO 31

20 PRINT AT 3J; .

30 NEXT I

When you run this program, a

TIMEX SINCLAIR USER

ILLUSTRATION * Don Kletke

series of *s will be printed across
the screen. Notice how the speed
has increased. Let's create a single
* moving across the screen now. Be
sure to remember the key to the
movement effect from section (1),
Change statement 20

20 PRINT AT 3,1; .

and run the program again. The key
is the addition of the blank space
“ " inserted before the *.

PEEKs, POKEs and system
variables are used to obtain a
smooth vertical motion when mov¬
ing a single character. The motion
will be as smooth and fast as
horizontal motion.

These definitions are needed to
understand this method:

System Variables: These are fixed
memory locations in main memory
that contain “book-keeping" infor¬
mation on the state of the com¬
puter. The PEEK statement is a

method of looking into this area
and seeing what is contained. The
POKE statement allows you to place
a number into that location.

D-FILE System Variable: This
variable contains the start of the
display file. The actual address of
the start is a changeable number,
the size of which is dependent upon
the size of your program. The
display file is the location of all the
characters that are visible on the
screen.

TIMEX SINCLAIR USER

Figure 1

5 REM SET D EQUAL TO START OF
DISPLAY FILE

10 LET D =256 +FEEK 16397+PEEK 1
639&

13 REM START OF POKE ANIMATION
15 PRINT AT 12. IS; "POKE
17 REM PRINTS R * ACROSS THE
SCREEN

20 FOR 1-34 TO 64
30 POKE I+D,0

40 POKE 1+041=23

50 NEXT I

55 REM PRINTS * DO UN THE
SCREEN

60 FOR 1=65 TO 623 STEP 33
70 POKE D+I , O
SO POKE D+I +33, 23
90 NEXT I

93 REM START OF PRINT RT

SECTION

95 PRINT AT 12,15; "PRINT6'

97 REM PRINTS A * ACROSS THE
SCREEN

100 FOR 1=31 TO 1 STEP -1
110 PRINT AT 19,1-1;"* "

120 NEXT I

130 FOR 1-19 TO 2 STEP -1

140 PRINT AT 1,0;" " ; AT 1-1,0; 11

150 NEXT X

152 REM START OF PLOT SECTION
155 PRINT AT 12.15: "PLOT "

157 REM PLOTS LEFT TO RIGHT
160 FOR 1=4 TO 53
170 UNPLOT 1-1,33
130 PLOT 1,38

190 NEXT I

191 PEM PLOTS DOWN

200 FOR 1=33 TO 5 STEP -1
210 UNPLOT 53,1
220 PLOT 53,1-1
230 NEXT I

235 REM PLOTS RIGHT TO LEFT

240 FOR 1=58 TO 4 STEP -I

250 UNPLOT 1+1,4

260 PLOT I , 4

£70 NEXT I

275 REM PLOTS UP

230 FOR 1=4 TO 37

290 UNPLOT 4,1

300 PLOT 4,1+4

310 NEXT

315 REM START THE WHOLE THING
OUEP AGAIN
320 GOTO 10

Here is a graphic representation
of the memory:

SYSTEM

PROGRAM

DISPLAY

OTHER

VARIABLES

AREA

FILE

AREAS

for the screen. Try this sequence:

10 LET D- 256* PEEK 16397 + PEEK 16396
20 POKE D + 1,23

What you will see is an * appear¬
ing at row 0, column 0, on your
screen; i.e., start of screen address
+ 1.

To access any point on the screen
add the position number to the star¬
ting address of the screen which is:

256* PEEK 16397 + PEEK 16396

Using Appendix A of the T/S1000
ZX81 manual look up the various
codes of the characters and poke
them into the various locations on
the screen. Example: (a) Set
D^256*PEEK 16397 + PEEK16396
(D - the start of the display), (b) Find
the code of the * character; this
turns out to be 23 (first column in
the Appendix A table), (c) Print the
* on the second row third column
POKE D + 36,23, then press ENTER
(33 spaces across the first line +
three spaces on the second line).

The * will appear upon initiating
the last statement.

The POKE statement replaces the
complicated PRINT at statements.
The POKE contains fewer machine
code components and thus ex¬
ecutes the program a little faster.

To erase a character, POKE a 0 in¬
to that location.

The program in figure 1 il¬
lustrates the three different speeds
of motion across the screen. It will
continually run, displaying the
titles POKE, print and PLOT during
which time either the * or the pixel
will run around the screen, using
the statement indicated on the
screen. The program will clearly
compare the speeds and
smoothness of motion for the three
animation methods.

16384 16509 ?

The display file address occupies
two bytes of storage [16396 and
16397). Thus to access the address
you use the statement;

LET D* 256*PEEK 16397 + PEEK 16396

after which D will contain the ad¬
dress of the first character position

N OW that you have mastered
motion on the screen, the next
stage is to control the direc -
lion of the motion from the
keyboard. To do this, you must
use the inkey$ function.

TIMEX SINCLAIR USER

This function: (1) has no
arguments; (2) reads the keyboard;
(3) doesn't wait for you, so you
don't have to type ENTER,

When you use the function, ac¬
tion will be taken only if the
specified key has been pressed.

The short program in figure 2 will
allow you to move an * across the
screen. The * will move left when
you press the 7 key and move right
when you press the 0 key, (The * ap¬
pears after you press either the 7
key or the 0 key to start,)

Now to move the * up and down,
add the lines in figure 3 to your pro¬
gram, (Statements 58 and 59 create
the effect of movement,) This pro¬
gram is the basis for an arcade type
game.

Firing At The Invaders

The next stage is to add a firing
feature. You must have some way
of destroying those “invading alien
hordes”. These statements are once
again an offshoot of the same
method of creating motion. Add
these lines to your program:

57 IF K$ = "L” THEN GOSUB 1000
1000 FOR I * C + 2 TO 30
1005 PRINT AT Rpl;

1010 NEXT I
1020 RETURN

When you press L the program
goes to the subroutine at statement
1000. This initiates a firing se¬
quence by printing a dash (-) across
the screen. If you wish to see the
line of fire, simulating a laser, take
the blank out of statement 1005,

Checking In Front Of You

In summary, the program allows
movement up, down, left, and right.
It can fire lasers or rockets. The last
detail is a quick check to see if you
have hit anything. To do this you
can use the system variable of DF-
CC at memory addresses 16398 and
16399.

To use this feature add the
lines in figure 3 to your program.

Figure 2

Program

Explanation

10 LET C- 10

Initializes the column to 10

20 LET K$= INKEYS

Sets K$, will contain the Jcey value
you press

30 IF K$* ‘"’THEN GOTO 20

Loop waits for you to press a key
(INKEY $ is an ongoing search
process)

40 IF K$ - “7” AND C - 2 THEN LET

Checks to see if you have pressed

G-C-l

a “7”. If so, and you aren’t at the
leji border, the column number is
decreased, (i.e. the will be

printed one column to the ie/t of
the old location.

50 IF K$ - 1 ■0" AND C - 29 THEN LET

Checks to see if you pressed “0”.

If so, and you aren’t at the right

C = C + 1

border, the column number is in¬
creased. (I.e. the * will be printed
one column to the right of the old
location.

60 PRINT AT 15,C;‘,,M

Prints the *. Notice the blanks on
either side of the *. (Remember
what they do?J

70 GOTO 20

Figure 2A

5 LET R = 2

55 IF K$ = *‘l" AND R-LTHEN LET

Checks to see if the f,l” key has

R-R-l

been pressed, moving the up.

56 IF K$- “4" AND R = 16 THEN LET

Checks to see if the “4” key has

R = R + 1

been pressed, moving the ,f*”
down.

58 PRINT AT R-1,C:“ "

Prints a blank above the ,

59 PRINT AT R + 1.C: “ ”

60 PRINT AT R,C; 11 *’*

Prints a blank below the l<*”

Figure 3

1006 PRINT AT R .1 + 2

1007 LET P = PEEK(2 56* PE EK

16399 + PEEK 16398)

1008 IF P = 155 THEN GOTO 200

2000 PRINT AT R.I-3; "BANG”

2005 PAUSE 30

2010 PRINT AT R.I-3;" AT R.I; .

2020 GOTO 40

Checks screen position. If the byte
contains the start of the alien then
it branches out to 2000 where a
message is printed out. In other
words you have made a direct hit!

TIMEX SINCLAIR USER

i uP'c°niing Events

Federal Computer
Conference, Washington D r
Sept. Peripherals,8^" D C

Sent Callf”™ie

Sent tis is r j. LaJlfornia
Expo. Ind!,an1SS7P“lOT
S*7,6.I,,.Hear,‘:;Te"afM

Computer She. San aASnto„lo.

SePMfc0roserral Coi"Puters 4
CaX T°ro"'°. Ontario. >1

aae-ssar

tendon. England
Sept. 29-Oct. 2: Computer
Show* Expo, San

tf**?*' *°

eoirtwwo? , w

On Hams

An Alabama company has a
series of programs for
operators of ham radios, in¬
cluding contest ’ dupe’' sheet,
antenna design and electronics
math; forthcoming are tapes
to help one prepare for a ham
radio license. For more infor¬
mation, contact Ken carpenter
(KC4UC) at Kentronics, P.0, box
586, Vernon, Alabama 35592, or
circle 40 on reader service can!

“soowr

^Master
10 percent

K Pnd^ line of

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Use this

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To obtain more information on any adver¬
tiser or product in Timex Sinclair User, cir*
cle the appropriate number on the reader
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ElOl

WHAT DO YOU WANT
FOR YOUR
TIMEX SINCLAIR?

• Applications

$ IN WARE provides these quality
machine code programs for the ZXSlf
TS1000

STEP

STEP provides line-at-a-time execu¬
tion of your BASIC programs and
shows you the display and variable
values to pinpoint programming er
rors, Set line breakpoints, loop break
points, or conditional breaks for fast
testing of long routines. STEP oc
copies 3K at the top of your 16K RAM
as you write and test new programs.
Detailed documentation. The final
solution for BASIC bugs.

Z-TOOLS

Z TOOLS lets you merge programs
from tape, renumber lines (including
GOTOs and GGSUBs) for neat listings,
copy and delete program blocks for
quick restructuring, or verify tape con¬
tents against memory to eliminate pro*
gram losses. Supplied in two versions,
for the top of a 16K RAM pack or for
the 8-1QK block of expanded RAM.

HOTZ

HOT Z disassembles, debugs, and lets
you copy and edit machine code pro¬
grams. If you can move a cursor
around and understand hex numbers,
you can use HOT Z almost at once.
Provides beautiful assembly listings,
addressable cassette functions, runs
your ZX printer (or Memotech t/F),
even disassembles the ZX floating
point language You owe your ZX. TX
a fresh dose of HOT Z

• Utilities

• Games

• Expansions

• News and Reviews

• Practical Advice

Get all this every month with SYNTAX newsletter.
Everything you need to get the most from your ZX/TS
computer. Just $29 for a full year of SYNTAX,
devoted to your computer*

Order yours today.

617/456-3661

MC/VISA/AMEX/DINERS

Z EXTRA

Z EXTRA is a display manages and
data filer that lets you enter text, data
or pictures directly to the screen and
save them in groups in memory, on
tape or in print. Display them sequenti¬
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use them in your BASIC programs.
Give your computer a completely new
personality with Z EXTRA.

PRICES Add S2 00 for postage

STEP . Cassette $14 95

2 TOOLS . Cassette $14 95

Z EXTRA . Cassette $19 95

HOT 2 16K or 32K + Cassette $19 96

HOT Z E . . Four 2716 EPROMs $40 00

SINWARE

Bon 8032

Santa Fe, NM 87504

SYNTAX RD 2 Box 457,
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For more information,
circle 36 on reader service 001x1,

For more information, circle 39 on reader service card.

TIMEX SINCLAIR USER

Send FREE

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NEW ,ro"J^500rZX81caSo9 *‘'ltake

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I Please RUSH my FREE catalog to me Today!

;IH

Name

1585 Kenmore Ave. , Buffalo, N.Y. 14217
ORDER TOLL-FREE 800-833-8400
In New York 716-874-5510

r further information (716) 074-551 (

For further Information (7l 6) 074-5510
In Canada call toll free 1-800-268-3640
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Address

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BUY A BANANA. SAVE A BUNCH.

Meet the Banana!“the very
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At $249.95 retail it’s an ideal
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After that, it’s merely com¬
parable to other printers that can
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10" carriages (to handle standard
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capability, 10 characters per inch
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rint (for perfectly acceptable
brm letters, data processing.

business reports, etc.) tractor
feed (for precise alignment and
quick loading), parallel or serial
interface (take your pick), self-
inking ribbon cassette (for long
life and easy installation), 10
portable pounds in weight, and
compatibility with so many of the
most popular personal computers
on the market

Plus its printhead features a
unique single- hammer design that
eliminates a lot of moving parts, to
eliminate a lot of annoying repairs.

That’s the Banana: silly name,
serious service. It’s everything
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Except expensive.

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Toll-free: 1-8 - * * — . . . . . .

-800-343-6833; In Massachusetts (617) 828-8150. Telex 951-624.

For more information, circle 35 an Render Service Card.

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